Merge branch 'feature/13' into dev

todo(13): done
test(handler): add tests for LocalStorageHandler
2026-03-14 05:02:56 +01:00 · 2026-03-14 05:02:55 +01:00 · 2026-03-14 04:57:32 +01:00 · 2026-03-14 04:55:37 +01:00 · 2026-03-14 04:39:24 +01:00 · 2026-03-14 04:34:13 +01:00
25 changed files with 3598 additions and 322 deletions
--- a/.gitmodules
+++ b/.gitmodules
@ -0,0 +1,3 @@
+[submodule "vendor/tiara-gitflow-spec"]
+	path = vendor/tiara-gitflow-spec
+	url = git@bitbucket.org:byteb4rb1e/tiara-gitflow-spec.git
--- a/README.md
+++ b/README.md
@ -1,33 +1,89 @@
 # esm-logging

-> This README is a stub. Working on it. Currently stabilizing the build
-  environment after that I'll make it nice around here.
+A quasi-port of the Python standard library
+[logging](https://docs.python.org/3/library/logging.html) module to
+ECMAScript. Browser-compatible, zero dependencies.

-A quasi-port of the Python standard library logging module to ECMAScript.
+## Why?

-# Why?
-
-First of, because logging is important. It is important for debugging purposes,
-leading to faster and more resilient development, for traceability leading to
-better security. Most logging libraries I've discovered didn't satisfy me,
-introduced weird concepts and all in all just weren't great. Other programming
-language ecosystems offer way nicer logging facilities. Take Rust for example,
-or... Python! Python has PEP, giving it a very structured approach towards
+Logging is important. It is important for debugging purposes, leading to
+faster and more resilient development, for traceability leading to better
+security. Most logging libraries I've discovered didn't satisfy me, introduced
+weird concepts and all in all just weren't great. Other programming language
+ecosystems offer way nicer logging facilities. Take Rust for example, or...
+Python! Python has PEP, giving it a very structured approach towards
 implementing new features and that's also how its logging facilities came to be
-([PEP 282](https://peps.python.org/pep-0282/)). Python's logging facilities are
-implemented by the [logging]() module, which is part of the standard library and
-has been since 2002. It was originally authored by Vinay Sajip
+([PEP 282](https://peps.python.org/pep-0282/)). Python's logging facilities
+are implemented by the [logging](https://docs.python.org/3/library/logging.html)
+module, which is part of the standard library and has been since 2002. It was
+originally authored by Vinay Sajip.

-# Roadmap
+## Installation

- do a quasi-port of the logging module with minimal amount of adaption
- add documentation
- add support for asynchronous calls
- implement Open Cybersecurity Framework (OCSF) formatter
- implement (Browser) local storage handler as a replacement for file handler
+```bash
+npm install @administratrix/esm-logging
+```

-# Usage
+## Quick start

-For the time being, please check out my [CI
-service](https://bitbucket.org/byteb4rb1e/esm-logging/pipelines), for an idea on
-how to build this.
+```javascript
+import * as logging from '@administratrix/esm-logging';
+
+// one-shot configuration: sets up a console handler on the root logger
+logging.config.basicConfig({ level: logging.log_level.INFO });
+
+// create a logger for this module
+const logger = logging.manager.MANAGER.getLogger('myapp');
+
+logger.info('Application started');
+logger.warning('Something looks off');
+logger.error('Something went wrong');
+```
+
+## Concepts
+
+The logging system is built around four core components:
+
+- **Loggers** expose the interface that application code uses directly.
+- **Handlers** send log records to the appropriate destination (console,
+  stderr, custom writable streams).
+- **Formatters** control the layout of log records in the final output.
+- **Filters** provide fine-grained control over which records to output.
+
+Loggers are organized in a dot-separated hierarchy. A logger named `app.db`
+is a child of the logger named `app`. Log records propagate up the hierarchy,
+so a handler attached to `app` will also receive records from `app.db`.
+
+## Log levels
+
+| Constant   | Value | Purpose                                  |
+|------------|-------|------------------------------------------|
+| `CRITICAL` | 50    | A serious error, the program may not continue |
+| `ERROR`    | 40    | An error that prevented some operation   |
+| `WARNING`  | 30    | Something unexpected, but the software still works |
+| `INFO`     | 20    | Confirmation that things work as expected |
+| `DEBUG`    | 10    | Detailed diagnostic information          |
+| `NOTSET`   | 0     | All messages are processed               |
+
+## Documentation
+
+See [docs/](docs/README.md) for the full user guide and
+[docs/logging-cookbook.md](docs/logging-cookbook.md) for recipes and patterns.
+
+API reference can be generated with TypeDoc:
+
+```bash
+npm run build/doc
+```
+
+## Roadmap
+
+- [x] quasi-port of the logging module with minimal adaptation
+- [x] add documentation
+- [ ] add support for asynchronous calls
+- [ ] implement Open Cybersecurity Schema Framework (OCSF) formatter
+- [ ] implement browser local storage handler as a replacement for file handler
+
+## License
+
+UNLICENSED
--- a/239
+++ b/239
@ -1,51 +1,5 @@
-# TODO List for esm-logging
-
-This is a poor-man's issue tracker. I am not primarily a GitHub user so don't
-want to commit to their issue tracking feature, but my primary SVC service
-provider (Bitbucket) only offers paid integration into their issue tracker
-(Jira). I don't have the time (and patience) at the moment to analyze the best
-approach, so this file will have to suffice.
-
-It's a very simple concept: Track any issues (features, bugfixes, hotfixes) in
-here, assign a sequential number to it and use that number when branching.
-
-I will try to develop a format so that I can parse the file later on, should I
-decide to migrate to a real issue tracker. It's probably going to be Bugzilla,
-but for that my html-theme-ref project needs to stabilize first.
-
-## Format Specification
-
-The file uses Markdown conventions for formatting headers and other text block
-entitities, but SHOULD NOT be considered a Markdown file. That's why it has no
-definitive file extension.
-
-Each issue entry follows a structured format for easier parsing and future
-migration.  Issues MUST be **appended** to this file and never moved, to
-preserve Git diffing.
-
-### Issue Format
-
-```
-
-ID: [ISSUE-NUMBER]
-Type: [feature/bugfix/hotfix]
-Title: [Short title]
-Status: [open/in-progress/done]
-Priority: [low/medium/high]
-Created: [YYYY-MM-DD]
-Description: [Detailed explanation]
-
---
-```
-
- ISSUE-NUMBERs must be sequential
- truncation of description must be indentended so that every line starts at the
-  same column
- issues must be started with two LF
- issues must be terminated with two LF, then `---`
- issues may have a free-text field (epilog), which must be started with two LF.
-
-## Issues
+--ISSUE
+Content-Type: application/issue

 ID: 1
 Type: feature
@ -53,12 +7,14 @@ Title: string formatting utilities
 Status: in-progress
 Priority: high
 Created: 2025-05-01
+Relationships:
 Description: implement utilities for formatting strings. The formatting should
             be inspired by Python 3K PEP 3101 in addition to their standard
             library utilities starting from ver. 3.7. Optimizations should
             focus on V8 support.

---
+--ISSUE
+Content-Type: application/issue

 ID: 2
 Type: feature
@ -66,10 +22,193 @@ Title: describe development workflow in CONTRIBUTING.md
 Status: open
 Priority: medium
 Created: 2025-05-01
+Relationships:
 Description: It's a good idea to describe the development workflow, including
             branching strategies earlier on, so that if someone is interested
             in forking, they can pick up right away. It's not meant for
             contributions though. I'm currently not interested in external
             contributions.

---
+--ISSUE
+Content-Type: application/issue
+
+ID: 3
+Type: bugfix
+Title: modularize testing further
+Status: done
+Priority: high
+Created: 2025-05-01
+Relationships:
+Description: Since I am going to implement unit tests as well as integration
+             tests and probably some benchmarks, it makes sense to introduce
+             another sub-level directory for each type of test, say
+             tests/unit/, tests/integration, etc.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 4
+Type: feature
+Title: migrate testing framework from Jest to Mocha
+Status: in-progress
+Priority: high
+Created: 2025-05-01
+Relationships:
+Description: I really don't like behavior-driven testing, at least when it comes
+             to unit testing. It feels like Walldorf education... Where I need
+             to come up with an abstraction for describing my test. A function
+             has an input and gives an output. That's what I want to test. I'm
+             not trying to find the philosophical meaning of my functions...
+             Hopefully Mocha is the savior. I'm sticking to xUnit based testing
+             from now on.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 5
+Type: bugfix
+Title: fix critical bugs across core modules
+Status: done
+Priority: high
+Created: 2026-03-13
+Relationships:
+Description: multiple logic bugs prevent the library from functioning.
+             manager.ts getLogger() has an inverted type check and missing
+             return statement. config.ts basicConfig() assigns wrong option
+             fields (filemode instead of datefmt/style) and has unreachable
+             conditions. logger.ts isEnabledFor() always caches false,
+             _log() never calls handle(), and makeRecord() uses .keys()
+             instead of Object.keys(). handler.ts format() has no return
+             statement and is missing a formatter getter.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 6
+Type: feature
+Title: implement remaining Logger level methods
+Status: done
+Priority: high
+Created: 2026-03-13
+Relationships: dependsOn:5
+Description: Logger only implements debug(). The info(), warning(), error(),
+             and critical() methods are missing entirely. The _log() method
+             also needs to be completed so it actually calls handle() after
+             creating the LogRecord.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 7
+Type: feature
+Title: implement Formatter subsystem
+Status: done
+Priority: high
+Created: 2026-03-13
+Relationships: dependsOn:1
+Description: the three core Formatter methods are stubs returning placeholder
+             strings. PercentFormatterStyle._format() needs to perform actual
+             %-style field substitution against LogRecord attributes.
+             Formatter.formatTime() needs a JS Date/Intl-based implementation
+             replacing the Python time.strftime references.
+             Formatter.formatError() needs to format Error.stack into a
+             string. The datetime helper module is empty and needs time
+             formatting utilities.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 8
+Type: feature
+Title: implement browser-compatible Handler output
+Status: done
+Priority: high
+Created: 2026-03-13
+Relationships: dependsOn:5
+Description: StreamHandler has no emit() implementation and its constructor
+             ignores the stream parameter. The helper/stream module is a
+             stub that needs a browser-compatible Writable interface backed
+             by console output. FileHandler should be dropped or gated behind
+             a Node.js environment check since browser environments have no
+             filesystem write access. A ConsoleHandler targeting the browser
+             console API (console.log/warn/error by level) is the primary
+             output target.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 9
+Type: feature
+Title: implement Manager logger hierarchy
+Status: done
+Priority: high
+Created: 2026-03-13
+Relationships: dependsOn:5
+Description: Manager.getLogger() does not establish parent-child
+             relationships between loggers based on dot-separated names.
+             The Placeholder fixup logic is incomplete. Logger propagation
+             depends on this hierarchy being correctly built so that child
+             loggers forward records to parent handlers.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 10
+Type: feature
+Title: add documentation
+Status: done
+Priority: medium
+Created: 2026-03-13
+Relationships:
+Description: write user-facing documentation covering module usage, API
+             reference, and configuration. The docs/ directory has stubs
+             (README.md, logging-cookbook.md) that need to be fleshed out.
+             TypeDoc generates API docs from source but a prose guide with
+             examples is needed for onboarding.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 11
+Type: feature
+Title: add support for asynchronous calls
+Status: open
+Priority: low
+Created: 2026-03-13
+Relationships:
+Description: introduce async-aware logging so that handlers which perform
+             I/O (e.g. network, storage) do not block the caller. This may
+             involve an AsyncHandler base class or async emit() overloads,
+             and consideration of how log record ordering is preserved
+             across concurrent async contexts.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 12
+Type: feature
+Title: implement OCSF formatter
+Status: open
+Priority: low
+Created: 2026-03-13
+Relationships:
+Description: implement a Formatter subclass that outputs log records in
+             Open Cybersecurity Schema Framework (OCSF) format. This
+             enables structured security event logging compatible with
+             SIEM systems and security analytics tooling.
+
+--ISSUE
+Content-Type: application/issue
+
+ID: 13
+Type: feature
+Title: implement browser local storage handler
+Status: done
+Priority: medium
+Created: 2026-03-13
+Relationships: dependsOn:8
+Description: implement a Handler subclass that persists log records to
+             browser localStorage or IndexedDB as a replacement for
+             FileHandler in browser environments. Should support log
+             rotation by size or entry count to avoid exceeding storage
+             quotas.
--- a/docs/README.md
+++ b/docs/README.md
@ -1 +1,333 @@
-The doc/README.md
+# esm-logging user guide
+
+This guide covers the `@administratrix/esm-logging` library, a quasi-port of
+Python's `logging` module for ECMAScript. It targets browser environments and
+provides hierarchical, configurable logging with formatters, handlers, and
+filters.
+
+## Table of contents
+
+- [Basic usage](#basic-usage)
+- [Loggers](#loggers)
+- [Handlers](#handlers)
+- [Formatters](#formatters)
+- [Filters](#filters)
+- [Configuration](#configuration)
+- [Log record attributes](#log-record-attributes)
+
+## Basic usage
+
+The simplest way to start logging is with `basicConfig`:
+
+```javascript
+import * as logging from '@administratrix/esm-logging';
+
+logging.config.basicConfig({
+    level: logging.log_level.DEBUG,
+    format: '%(levelname)s:%(name)s:%(message)s',
+});
+
+const logger = logging.manager.MANAGER.getLogger('myapp');
+logger.info('Hello, world');
+// output: INFO:myapp:Hello, world
+```
+
+`basicConfig` creates a `StreamHandler` writing to stderr (via
+`console.error`) and attaches it to the root logger. It is a one-shot
+function: calling it again has no effect unless you pass `force: true`.
+
+## Loggers
+
+Loggers are the entry point for emitting log records. They are organized in a
+dot-separated hierarchy managed by a singleton `Manager`.
+
+### Creating loggers
+
+```javascript
+const logger = logging.manager.MANAGER.getLogger('myapp');
+const childLogger = logging.manager.MANAGER.getLogger('myapp.db');
+```
+
+Calling `getLogger` with the same scope always returns the same logger
+instance. The hierarchy is established automatically: `myapp.db` is a child of
+`myapp`.
+
+### Setting levels
+
+```javascript
+logger.setLevel(logging.log_level.WARNING);
+```
+
+A logger only processes messages at or above its effective level. The
+effective level is determined by walking up the parent chain until a logger
+with a non-zero level is found. The root logger defaults to `WARNING`.
+
+### Logging methods
+
+Each level has a corresponding method:
+
+```javascript
+logger.debug('Detailed diagnostic info');
+logger.info('Things are working');
+logger.warning('Something unexpected');
+logger.error('An operation failed');
+logger.critical('System is in trouble');
+```
+
+### Propagation
+
+By default, log records propagate up the hierarchy. A record emitted by
+`myapp.db` will be handled by handlers on `myapp.db`, then `myapp`, then the
+root logger. This means you typically only need to configure handlers on the
+root logger or on high-level loggers.
+
+### Checking if a level is enabled
+
+```javascript
+if (logger.isEnabledFor(logging.log_level.DEBUG)) {
+    logger.debug('Expensive computation: ' + computeDebugInfo());
+}
+```
+
+This avoids the cost of building the message string when the level would be
+filtered out anyway.
+
+## Handlers
+
+Handlers determine where log records go. A logger can have multiple handlers,
+and each handler can have its own level and formatter.
+
+### Available handlers
+
+#### StreamHandler
+
+Writes formatted output to a `Writable` stream. Defaults to stderr (via
+`console.error`).
+
+```javascript
+import { StreamHandler } from '@administratrix/esm-logging/src/handler';
+import { ConsoleWritable } from '@administratrix/esm-logging/src/helper/stream';
+
+const handler = new StreamHandler(new ConsoleWritable());
+logger.addHandler(handler);
+```
+
+#### ConsoleHandler
+
+Maps log levels to the appropriate browser console method:
+
+- `ERROR` and `CRITICAL` use `console.error`
+- `WARNING` uses `console.warn`
+- `DEBUG` and `INFO` use `console.log`
+
+```javascript
+import { ConsoleHandler } from '@administratrix/esm-logging/src/handler';
+
+const handler = new ConsoleHandler();
+handler.level = logging.log_level.DEBUG;
+logger.addHandler(handler);
+```
+
+#### StderrHandler
+
+Always writes to `console.error`, regardless of level. Useful when you want
+all output on stderr.
+
+```javascript
+import { StderrHandler } from '@administratrix/esm-logging/src/handler';
+
+const handler = new StderrHandler(logging.log_level.WARNING);
+logger.addHandler(handler);
+```
+
+#### FileHandler
+
+Not available in browser environments. Throws `NotImplementedError` on
+construction. Use `ConsoleHandler` or a storage-backed handler instead.
+
+### Handler methods
+
+```javascript
+handler.level = logging.log_level.INFO;  // only handle INFO and above
+handler.formatter = myFormatter;         // set a custom formatter
+handler.close();                         // release resources
+```
+
+### Custom handlers
+
+Subclass `Handler` and implement `emit(record)`:
+
+```javascript
+import { Handler } from '@administratrix/esm-logging/src/handler';
+
+class ArrayHandler extends Handler {
+    constructor() {
+        super();
+        this.records = [];
+    }
+
+    emit(record) {
+        this.records.push(this.format(record));
+    }
+}
+```
+
+## Formatters
+
+Formatters control how log records are rendered as strings. The default format
+is `%(message)s` (just the message). The basic format used by `basicConfig` is
+`%(levelname)s:%(name)s:%(message)s`.
+
+### Creating a formatter
+
+```javascript
+import { Formatter } from '@administratrix/esm-logging/src/formatter';
+
+const formatter = new Formatter({
+    fmt: '%(asctime)s - %(levelname)s - %(name)s - %(message)s',
+    datefmt: '%Y-%m-%d %H:%M:%S',
+});
+
+handler.formatter = formatter;
+```
+
+### Format string placeholders
+
+Formatters use `%`-style substitution. Available placeholders correspond to
+[log record attributes](#log-record-attributes):
+
+```
+%(name)s        Logger scope name
+%(levelno)d     Numeric log level
+%(levelname)s   Text log level (DEBUG, INFO, etc.)
+%(message)s     The formatted message
+%(asctime)s     Human-readable timestamp
+%(created)f     Milliseconds since epoch (Date.now())
+```
+
+### Date formatting
+
+The `datefmt` option accepts strftime-style tokens:
+
+| Token | Meaning         | Example |
+|-------|-----------------|---------|
+| `%Y`  | Four-digit year | 2026    |
+| `%m`  | Zero-padded month | 03    |
+| `%d`  | Zero-padded day | 14      |
+| `%H`  | Hour (24h)      | 09      |
+| `%M`  | Minute          | 05      |
+| `%S`  | Second          | 30      |
+
+If `datefmt` is omitted, an ISO 8601-like format is used:
+`2026-03-14 09:05:30.123`.
+
+## Filters
+
+Filters provide fine-grained control over which records get processed. They
+can be attached to loggers or handlers.
+
+### Scope-based filtering
+
+A `Filter` initialized with a scope name only allows records from that scope
+and its children:
+
+```javascript
+import { Filter } from '@administratrix/esm-logging/src/filter';
+
+const filter = new Filter('myapp.db');
+handler.addFilter(filter);
+// only records from 'myapp.db' and 'myapp.db.*' will pass
+```
+
+A filter initialized with an empty string allows all records.
+
+### Custom filters
+
+Any object with a `filter(record)` method can be used:
+
+```javascript
+handler.addFilter({
+    filter(record) {
+        return record.levelno >= logging.log_level.WARNING;
+    }
+});
+```
+
+## Configuration
+
+### basicConfig
+
+`basicConfig` is a convenience function for simple, one-shot configuration of
+the root logger:
+
+```javascript
+logging.config.basicConfig({
+    level: logging.log_level.DEBUG,
+    format: '%(asctime)s %(levelname)s %(message)s',
+    datefmt: '%Y-%m-%d %H:%M:%S',
+});
+```
+
+#### Options
+
+| Option     | Type       | Description                                |
+|------------|------------|--------------------------------------------|
+| `level`    | `number`   | Root logger level                          |
+| `format`   | `string`   | Format string for the handler's formatter  |
+| `datefmt`  | `string`   | Date format string                         |
+| `style`    | `string`   | Format style (`'%'` only, currently)       |
+| `handlers` | `Handler[]`| Pre-built handlers to attach               |
+| `stream`   | `Writable` | Stream for the default StreamHandler       |
+| `force`    | `boolean`  | Remove existing handlers first             |
+
+`stream` and `handlers` are mutually exclusive.
+
+### Manual configuration
+
+For more control, configure loggers and handlers directly:
+
+```javascript
+const root = logging.manager.MANAGER.root;
+const handler = new ConsoleHandler();
+handler.level = logging.log_level.DEBUG;
+handler.formatter = new Formatter({
+    fmt: '%(asctime)s [%(levelname)s] %(name)s: %(message)s',
+});
+root.addHandler(handler);
+root.setLevel(logging.log_level.DEBUG);
+```
+
+## Log record attributes
+
+A `LogRecord` carries the following attributes:
+
+| Attribute   | Type     | Description                            |
+|-------------|----------|----------------------------------------|
+| `scope`     | `string` | Logger name that created the record    |
+| `name`      | `string` | Same as `scope`                        |
+| `levelno`   | `number` | Numeric level (10, 20, 30, 40, 50)    |
+| `levelname` | `string` | Text level (`DEBUG`, `INFO`, etc.)     |
+| `msg`       | `string` | The raw message template               |
+| `args`      | `any[]`  | Substitution arguments for `%s` in msg |
+| `message`   | `string` | The formatted message (set by formatter) |
+| `created`   | `number` | Milliseconds since Unix epoch          |
+| `asctime`   | `string` | Formatted timestamp (set by formatter) |
+
+The `getMessage()` method on `LogRecord` performs `%s` argument substitution
+on `msg` using `args`.
+
+## Module structure
+
+The library is organized into submodules, all re-exported from the main entry
+point:
+
+| Import path   | Contents                                     |
+|---------------|----------------------------------------------|
+| `config`      | `basicConfig()`                              |
+| `filter`      | `Filter`, `Filterer`                         |
+| `formatter`   | `Formatter`, `STYLES`, `DEFAULT_FORMATTER`   |
+| `handler`     | `Handler`, `StreamHandler`, `ConsoleHandler`, `StderrHandler`, `FileHandler` |
+| `log_level`   | Level constants, `getLevelName()`, `checkLevel()` |
+| `log_record`  | `LogRecord`, factory functions               |
+| `logger`      | `Logger`, `RootLogger`, `ROOT`               |
+| `manager`     | `Manager`, `MANAGER`                         |
--- a/docs/logging-cookbook.md
+++ b/docs/logging-cookbook.md
@ -1,37 +1,216 @@
-# Using logging in multiple modules
+# Logging cookbook

-Multiple calls to `logging.getLogger('someLogger')` return a reference to the
-same logger object. This is true not only within the same module, but also
-across modules as long as it is in the same Python interpreter process. It is
-true for references to the same object; additionally, application code can
-define and configure a parent logger in one module and create (but not
-configure) a child logger in a separate module, and all logger calls to the
-child will pass up to the parent. Here is a main module:
+Recipes and patterns for common logging tasks with `@administratrix/esm-logging`.

-``javascript
-import * as logging from 'eslib/logging';
-import * as my_module from './my_module';
+## Using logging across multiple modules

-// create logger with 'spam_application'
-var logger = logging.getLogger('spam_application');
-logger.setLevel(logging.DEBUG);
+`getLogger` returns the same logger instance for a given scope name across
+your entire application. Configure handlers on a parent logger and create
+child loggers in each module:

-// create file handler which logs even debug messages
-var fh = logging.FileHandler('spam.log')
-fh.setLevel(logging.DEBUG);
+```javascript
+// main.js
+import * as logging from '@administratrix/esm-logging';
+import { ConsoleHandler } from '@administratrix/esm-logging/src/handler';
+import { Formatter } from '@administratrix/esm-logging/src/formatter';
+import { doWork } from './worker.js';

-// create console handler with a higher log level
-var ch = logging.StreamHandler();
-ch.setLevel(logging.ERROR);
+const logger = logging.manager.MANAGER.getLogger('myapp');
+logger.setLevel(logging.log_level.DEBUG);

-// create formatter and add it to the handlers
-var formatter = logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s');
-fh.setFormatter(formatter);
-ch.setFormatter(formatter);
+const handler = new ConsoleHandler();
+handler.level = logging.log_level.DEBUG;
+handler.formatter = new Formatter({
+    fmt: '%(asctime)s - %(name)s - %(levelname)s - %(message)s',
+});
+logger.addHandler(handler);

-// add the handlers to the logger
-logger.addHandler(fh);
-logger.addHandler(ch);
-
-logger.info('creating an instance of auxiliary_module.Auxiliary')
+logger.info('Application starting');
+doWork();
+logger.info('Application finished');
 ```
+
+```javascript
+// worker.js
+import * as logging from '@administratrix/esm-logging';
+
+const logger = logging.manager.MANAGER.getLogger('myapp.worker');
+
+export function doWork() {
+    logger.debug('Starting work');
+    // ... do something ...
+    logger.info('Work completed');
+}
+```
+
+Because `myapp.worker` is a child of `myapp`, its records propagate up to the
+handler configured on `myapp`. No handler configuration is needed in
+`worker.js`.
+
+Output:
+
+```
+2026-03-14 10:00:00.000 - myapp - INFO - Application starting
+2026-03-14 10:00:00.001 - myapp.worker - DEBUG - Starting work
+2026-03-14 10:00:00.002 - myapp.worker - INFO - Work completed
+2026-03-14 10:00:00.003 - myapp - INFO - Application finished
+```
+
+## Logging to multiple destinations
+
+Attach multiple handlers to a single logger, each with its own level and
+formatter:
+
+```javascript
+import * as logging from '@administratrix/esm-logging';
+import { ConsoleHandler, StderrHandler } from '@administratrix/esm-logging/src/handler';
+import { Formatter } from '@administratrix/esm-logging/src/formatter';
+
+const logger = logging.manager.MANAGER.getLogger('myapp');
+logger.setLevel(logging.log_level.DEBUG);
+
+// console handler: shows everything with detailed format
+const consoleHandler = new ConsoleHandler();
+consoleHandler.level = logging.log_level.DEBUG;
+consoleHandler.formatter = new Formatter({
+    fmt: '%(asctime)s [%(levelname)s] %(name)s: %(message)s',
+});
+logger.addHandler(consoleHandler);
+
+// stderr handler: only errors, compact format
+const errorHandler = new StderrHandler(logging.log_level.ERROR);
+errorHandler.formatter = new Formatter({
+    fmt: 'ERROR %(asctime)s %(name)s: %(message)s',
+    datefmt: '%Y-%m-%d %H:%M:%S',
+});
+logger.addHandler(errorHandler);
+```
+
+## Using basicConfig for simple scripts
+
+For quick scripts, `basicConfig` sets up a handler on the root logger:
+
+```javascript
+import * as logging from '@administratrix/esm-logging';
+
+logging.config.basicConfig({
+    level: logging.log_level.INFO,
+    format: '%(levelname)s: %(message)s',
+});
+
+const logger = logging.manager.MANAGER.getLogger('script');
+logger.info('Running');
+logger.warning('Check this');
+```
+
+Output:
+
+```
+INFO: Running
+WARNING: Check this
+```
+
+## Filtering records
+
+### By scope
+
+Only allow records from a specific part of the hierarchy:
+
+```javascript
+import { Filter } from '@administratrix/esm-logging/src/filter';
+
+const dbFilter = new Filter('myapp.db');
+handler.addFilter(dbFilter);
+// handler now only processes records from 'myapp.db' and its children
+```
+
+### By custom criteria
+
+Use any object with a `filter(record)` method:
+
+```javascript
+handler.addFilter({
+    filter(record) {
+        // only pass records that contain 'important' in the message
+        return record.msg.includes('important');
+    }
+});
+```
+
+## Custom formatters
+
+Create formatters with different format strings for different contexts:
+
+```javascript
+import { Formatter } from '@administratrix/esm-logging/src/formatter';
+
+// detailed format for development
+const devFormatter = new Formatter({
+    fmt: '%(asctime)s %(levelname)s %(name)s: %(message)s',
+    datefmt: '%H:%M:%S',
+});
+
+// compact format for production
+const prodFormatter = new Formatter({
+    fmt: '%(levelname)s:%(name)s:%(message)s',
+});
+```
+
+## Custom handlers
+
+Subclass `Handler` and implement `emit(record)`:
+
+```javascript
+import { Handler } from '@administratrix/esm-logging/src/handler';
+
+class BufferHandler extends Handler {
+    constructor(level) {
+        super(level);
+        this.buffer = [];
+    }
+
+    emit(record) {
+        try {
+            this.buffer.push(this.format(record));
+            if (this.buffer.length >= 100) {
+                this.flush();
+            }
+        } catch (e) {
+            this.handleError(record);
+        }
+    }
+
+    flush() {
+        // send buffered records somewhere
+        const batch = this.buffer.splice(0);
+        // ... process batch ...
+    }
+}
+```
+
+## Disabling logging below a threshold
+
+The manager's `disable` property suppresses all logging at or below a given
+level across all loggers:
+
+```javascript
+import * as logging from '@administratrix/esm-logging';
+
+// suppress DEBUG and INFO globally
+logging.manager.MANAGER.disable = logging.log_level.INFO;
+```
+
+## Reconfiguring with force
+
+`basicConfig` only takes effect once. To reconfigure, use `force: true`:
+
+```javascript
+logging.config.basicConfig({
+    level: logging.log_level.DEBUG,
+    format: '%(asctime)s %(message)s',
+    force: true,
+});
+```
+
+This removes and closes all existing handlers on the root logger before
+applying the new configuration.
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@ -0,0 +1,7 @@
+import eslint from "@eslint/js";
+import tseslint from "typescript-eslint";
+
+export default tseslint.config(
+    eslint.configs.recommended,
+    tseslint.configs.recommended,
+);
--- a/jest.config.mjs
+++ b/jest.config.mjs
@ -19,5 +19,5 @@ export default {
            }
        ],
    ],
-    roots: ['./tests']
+    roots: ['./tests/unit']
 }
--- a/package-lock.json
+++ b/package-lock.json
--- a/package.json
+++ b/package.json
@ -3,14 +3,15 @@
    "version": "1.0.0",
    "description": "port of Python standard library logging module",
    "main": "lib/index.js",
+    "engines": {
+        "node": ">= 20.11.0"
+    },
    "scripts": {
-        "test": "jest",
-        "build": "npm run build:release",
-        "build:release": "tsc",
-        "build:debug": "tsc -p tsconfig.debug.json",
-        "doc": "typedoc --entryPoints src/index.ts --html build/doc",
-        "publish_": "ts-node -P tsconfig.node.json scripts/publish.ts",
-        "dist": "ts-node -P tsconfig.node.json scripts/npm-pack.ts build/release dist"
+        "build/debug": "tsc -p tsconfig.debug.json",
+        "build/release": "tsc",
+        "build/doc": "typedoc",
+        "dist": "ts-node -P tsconfig.node.json scripts/npm-pack.ts build/release dist",
+        "test-reports/unit": "jest"
    },
    "repository": {
        "type": "git",
@ -19,13 +20,16 @@
    "author": "Tiara Rodney",
    "license": "UNLICENSED",
    "devDependencies": {
+        "@eslint/js": "^9.39.4",
        "@types/jest": "^29.5.14",
+        "eslint": "^9.39.4",
        "jest": "^29.7.0",
        "jest-junit": "^16.0.0",
        "ts-jest": "^29.3.2",
        "ts-node": "^10.9.2",
        "typedoc": "^0.28.3",
-        "typescript": "^5.8.3"
+        "typescript": "^5.8.3",
+        "typescript-eslint": "^8.57.0"
    },
    "overrides": {
        "jest": {
--- a/src/config.ts
+++ b/src/config.ts
@ -121,8 +121,8 @@ export function basicConfig(options: BasicConfigOptions) {
    const filename = options.filename ?? null;
    const stream = options.stream ?? null;
    const filemode = options.filemode ?? 'a';
-    const dateformat = options.filemode ?? null;
-    const style = options.filemode ?? '%';
+    const dateformat = options.datefmt;
+    const style = options.style ?? '%';
    const level = options.level ?? null;

    if (!Object.keys(STYLES).includes(style)) {
@ -139,64 +139,54 @@ export function basicConfig(options: BasicConfigOptions) {
        }
    }

-    if (handlers.length == 0) {
-        if (handlers === null && stream && filename) {
+    if (MANAGER.root.handlers.length > 0 && !force) {
+        return;
+    }
+
+    if (handlers.length > 0) {
+        if (stream || filename) {
+            throw new ValueError(
+                "'stream' or 'filename' should not be specified together " +
+                "with 'handlers'"
+            );
+        }
+    }
+    else {
+        if (stream && filename) {
            throw new ValueError(
                "'stream' and 'filename' should not be specified together"
            );
        }

-        else if (stream || filename) {
-            throw new ValueError(
-                "'stream' or 'filename' should not be specified together" +
-                "with 'handlers'"
-            );
+        if (filename) {
+            if (filemode.match('b')) { errors = undefined }
+            else { encoding = 'utf-8' }
+
+            handlers = [new FileHandler({
+                filename: filename,
+                filemode: filemode,
+                encoding: encoding,
+                errors: errors
+            })];
        }
-
-        if (handlers === null) {
-            var h: Handler;
-
-            if (filename) {
-                if (filemode.match('b')) { errors = undefined }
-                else { encoding = 'utf-8' }
-
-                h = new FileHandler({
-                    filename: filename,
-                    filemode: filemode,
-                    'encoding': encoding,
-                    errors: errors
-                });
-            }
-
-            else { h = new StreamHandler(stream) }
-
-            handlers = [h];
-        }
-
-        for (var i = 0; i < handlers.length; i += 1) {
-            let h = handlers[i];
-
-            if (h.formatter === null) {
-                h.formatter = new Formatter({
-                    fmt: options.format ?? STYLES[style][1],
-                    datefmt: dateformat,
-                    style: style
-                });
-            }
-
-            MANAGER.root.addHandler(h);
-        }
-
-        if (level !== null) { MANAGER.root.setLevel(level) }
-
-        if (options) {
-            // runtime interface guard, please let me stay. 🥺
-            // the interface does not allow for additional members, but the
-            // runtime environment has no concept of interfaces. We can stick to
-            // the original implementation
-            const keys = Object.keys(options).join(', ');
-
-            throw new ValueError(`Unrecognised argument(s): ${keys}`);
+        else {
+            handlers = [new StreamHandler(stream)];
        }
    }
+
+    for (let i = 0; i < handlers.length; i += 1) {
+        const h = handlers[i];
+
+        if (h.formatter === null) {
+            h.formatter = new Formatter({
+                fmt: options.format ?? STYLES[style][1],
+                datefmt: dateformat,
+                style: style
+            });
+        }
+
+        MANAGER.root.addHandler(h);
+    }
+
+    if (level !== null) { MANAGER.root.setLevel(level) }
 }
--- a/src/formatter.ts
+++ b/src/formatter.ts
@ -10,6 +10,12 @@ export interface PercentFormatterStyleOptions {
    defaults: {[key: string]: any};
 }

+/**
+ * %-style formatting for log records.
+ *
+ * Substitutes %(name)s, %(name)d, %(name)f placeholders from record
+ * attributes.
+ */
 class PercentFormatterStyle {
    public static defaultFormat = '%(message)s';
    public static asctimeFormat = '%(asctime)s';
@ -17,7 +23,7 @@ class PercentFormatterStyle {
    public static validationPattern =
        /%\(\w+\)[#0+ -]*(\*|\d+)?(\.(\*|\d+))?[diouxefgcrsa%]/;

-    private fmt: string;
+    public fmt: string;
    private defaults: {[key: string]: any};

    constructor(options: PercentFormatterStyleOptions) {
@ -26,7 +32,7 @@ class PercentFormatterStyle {
    }

    usesTime(): boolean {
-        return  this.fmt.match(PercentFormatterStyle.asctimeFormat) ? true : false
+        return this.fmt.indexOf(PercentFormatterStyle.asctimeSearch) >= 0;
    }

    /**
@ -42,12 +48,32 @@ class PercentFormatterStyle {
    }

    protected _format(record: LogRecord): string {
-        var defaults = this.defaults;
-        var values: {[key: string]: any}|null;
-        if (defaults) { values = {...this.defaults, ...Object.entries(record)} }
-        else { values = Object.entries(record) }
-        //TODO: implement formatting
-        return 'would do some formatting';
+        const values: {[key: string]: any} = {
+            ...this.defaults,
+            ...(record as unknown as {[key: string]: any}),
+        };
+
+        return this.fmt.replace(
+            /%\((\w+)\)([#0+ -]*(?:\*|\d+)?(?:\.(?:\*|\d+))?[diouxefgcrsa%])/g,
+            (_match, key, spec) => {
+                if (!(key in values)) {
+                    throw new ValueError(`formatting field not found in record: ${key}`);
+                }
+                const val = values[key];
+                const conversion = spec[spec.length - 1];
+                switch (conversion) {
+                    case 'd':
+                    case 'i':
+                        return String(Math.floor(Number(val)));
+                    case 'f':
+                        return String(Number(val));
+                    case 's':
+                        return String(val);
+                    default:
+                        return String(val);
+                }
+            }
+        );
    }

    format(record: LogRecord): string {
@ -55,12 +81,13 @@ class PercentFormatterStyle {
            return this._format(record)
        }
        catch (e) {
+            if (e instanceof ValueError) { throw e }
            throw new ValueError(`formatting field not found in record: ${e}`)
        }
    }
 }

-const BASIC_FORMAT = '%(level)s:%(name)s:%(message)s';
+const BASIC_FORMAT = '%(levelname)s:%(name)s:%(message)s';

 export const STYLES: {[key: string]: [{ new(options: PercentFormatterStyleOptions): PercentFormatterStyle}, string]} = {
    '%': [PercentFormatterStyle, BASIC_FORMAT],
@ -68,7 +95,7 @@ export const STYLES: {[key: string]: [{ new(options: PercentFormatterStyleOption

 export interface FormatterOptions {
    fmt?: string
-    datefmt?: any
+    datefmt?: string
    style?: string
    validate?: boolean
    defaults?: {[key: string]: any}
@ -95,53 +122,26 @@ export interface FormatterOptions {
 *                     WARNING, ERROR, CRITICAL)
 * %(levelname)s       Text logging level for the message ("DEBUG", "INFO",
 *                     "WARNING", "ERROR", "CRITICAL")
- * %(pathname)s        Full pathname of the source file where the logging
- *                     call was issued (if available)
- * %(filename)s        Filename portion of pathname
- * %(module)s          Module (name portion of filename)
- * %(lineno)d          Source line number where the logging call was issued
- *                     (if available)
- * %(funcName)s        Function name
- * %(created)f         Time when the LogRecord was created (time.time_ns() / 1e9
+ * %(created)f         Time when the LogRecord was created (Date.now()
 *                     return value)
 * %(asctime)s         Textual time when the LogRecord was created
- * %(msecs)d           Millisecond portion of the creation time
- * %(relativeCreated)d Time in milliseconds when the LogRecord was created,
- *                     relative to the time the logging module was loaded
- *                     (typically at application startup time)
- * %(thread)d          Thread ID (if available)
- * %(threadName)s      Thread name (if available)
- * %(taskName)s        Task name (if available)
- * %(process)d         Process ID (if available)
 * %(message)s         The result of record.getMessage(), computed just as
 *                     the record is emitted
 */
 export class Formatter {
-    public static defaultTimeFormat = '%Y-%M';
-    public static defaultMsecFormat = '%s,%30d';
+    public static defaultTimeFormat = 'YYYY-MM-DDTHH:mm:ss';
+    public static defaultMsecFormat = '%s.%03d';

-    protected style: any;
+    protected style: PercentFormatterStyle;
    protected fmt: string;
-    protected datefmt: any;
+    protected datefmt: string|undefined;

-    /**
-     * Initialize the formatter with specified format strings.
-     *
-     * Initialize the formatter either with the specified format string, or a
-     * default as described above. Allow for specialized date formatting with
-     * the optional datefmt argument. If datefmt is omitted, you get an
-     * ISO8601-like (or RFC 3339-like) format.
-     *
-     * Use a style parameter of '%', '{' or '$' to specify that you want to
-     * use one of %-formatting, :meth:`str.format` (``{}``) formatting or
-     * :class:`string.Template` formatting in your format string.
-     */
    constructor(options?: FormatterOptions) {
        options = options ?? {};
-        var style = options.style ?? '%';
-        var validate = options.validate ?? true;
+        const style = options.style ?? '%';
+        const validate = options.validate ?? true;

-        if (!Object.keys(STYLES).includes(style ?? '')) {
+        if (!Object.keys(STYLES).includes(style)) {
            throw new ValueError(`style must be one of: ${Object.keys(STYLES).join(', ')}`)
        }

@ -157,45 +157,60 @@ export class Formatter {
        this.datefmt = options.datefmt;
    }

+    usesTime(): boolean {
+        return this.style.usesTime();
+    }
+
+    /**
+     * Format the specified record as text.
+     *
+     * The record's attribute dictionary is used as the operand to a string
+     * formatting operation which yields the returned string. Before the
+     * formatting operation, a couple of preparatory steps are carried out.
+     * The message attribute of the record is computed using LogRecord.getMessage().
+     * If the formatting string uses the time, formatTime() is called to format
+     * the event time.
+     */
+    format(record: LogRecord): string {
+        record.message = record.getMessage();
+
+        if (this.usesTime()) {
+            record.asctime = this.formatTime(record, this.datefmt);
+        }
+
+        return this.style.format(record);
+    }
+
    /**
     * Return the creation time of the specified LogRecord as formatted text.
     *
-     * This method should be called from format() by a formatter which
-     * wants to make use of a formatted time. This method can be overridden
-     * in formatters to provide for any specific requirement, but the
-     * basic behaviour is as follows: if datefmt (a string) is specified,
-     * it is used with time.strftime() to format the creation time of the
-     * record. Otherwise, an ISO8601-like (or RFC 3339-like) format is used.
-     * The resulting string is returned. This function uses a user-configurable
-     * function to convert the creation time to a tuple. By default,
-     * time.localtime() is used; to change this for a particular formatter
-     * instance, set the 'converter' attribute to a function with the same
-     * signature as time.localtime() or time.gmtime(). To change it for all
-     * formatters, for example if you want all logging times to be shown in GMT,
-     * set the 'converter' attribute in the Formatter class.
+     * If datefmt is specified, it is used as a strftime-style format string.
+     * Supported tokens: %Y, %m, %d, %H, %M, %S.
+     * Otherwise, an ISO8601-like format is used.
     */
-    formatTime(record: LogRecord, datefmt?: any): string {
+    formatTime(record: LogRecord, datefmt?: string): string {
+        const dt = new Date(record.created);

-        //TODO: record.created
        if (datefmt) {
-            //TODO: time.strftime
-        }
-        else {
-            //TODO: time.strftime
+            return datefmt
+                .replace('%Y', String(dt.getFullYear()))
+                .replace('%m', String(dt.getMonth() + 1).padStart(2, '0'))
+                .replace('%d', String(dt.getDate()).padStart(2, '0'))
+                .replace('%H', String(dt.getHours()).padStart(2, '0'))
+                .replace('%M', String(dt.getMinutes()).padStart(2, '0'))
+                .replace('%S', String(dt.getSeconds()).padStart(2, '0'));
        }

-        return 'some time';
+        const iso = dt.toISOString();
+        return iso.replace('T', ' ').replace('Z', '');
    }

    /**
     * Format and return the specified exception information as a string.
-
-     * This default implementation just uses
-     * traceback.print_exception()
     */
    formatError(ei: MyError): string {
-        //TODO
-        return 'some error';
+        if (ei.stack) { return ei.stack }
+        return String(ei);
    }
 }

--- a/src/handler.ts
+++ b/src/handler.ts
@ -1,17 +1,9 @@
-import * as stream from 'stream';
-
-import { LogLevel, checkLevel, NOTSET } from './log-level';
+import { LogLevel, checkLevel, NOTSET, WARNING, ERROR } from './log-level';
 import { LogRecord } from './log-record';
 import { Formatter, DEFAULT_FORMATTER } from './formatter';
 import { Filterer } from './filter';
 import { NotImplementedError } from './helper/error';
-
-if (typeof window === 'undefined') {
-    const stream = require('stream');
-}
-else {
-    const stream = require('./helper/stream');
-}
+import { Writable, DEFAULT_STREAM, StderrWritable } from './helper/stream';

 //---------------------------------------------------------------------------
 // Handler classes and functions
@ -78,7 +70,7 @@ export class Handler extends Filterer {
    }

    get level(): number { return this._level }
-    set level(level: LogLevel|string) { this.level = checkLevel(level) }
+    set level(level: LogLevel|string) { this._level = checkLevel(level) }

    get scope(): string|null { return this._scope }
    set scope(scope: string) { this._scope = scope }
@ -90,11 +82,9 @@ export class Handler extends Filterer {
     * If a formatter is set, use it. Otherwise, use the default formatter for
     * the module.
     */
-    format(record: LogRecord) {
-        var fmt: Formatter|null = null;
-
-        if (this.formatter) { fmt = this.formatter }
-        else { fmt = DEFAULT_FORMATTER }
+    format(record: LogRecord): string {
+        const fmt = this.formatter ?? DEFAULT_FORMATTER;
+        return fmt.format(record);
    }

    /**
@ -117,14 +107,13 @@ export class Handler extends Filterer {
     * I/O thread lock.
     */
     handle(record: LogRecord) {
-        var rv = this.filter(record);
+        const rv = this.filter(record);
+        if (!rv) { return }
+        let filtered = record;
        if ((rv as any) instanceof LogRecord) {
-            record = rv as unknown as LogRecord
-        }
-        if (rv) {
-            //locking here
-            this.emit(record)
+            filtered = rv as unknown as LogRecord
        }
+        this.emit(filtered)
    }

    /**
@ -146,22 +135,73 @@ export class Handler extends Filterer {
     * Handle errors which occur during an emit() call.
     *
     * This method should be called from handlers when an exception is
-     * encountered during an emit() call. If raiseExceptions is false,
-     * exceptions get silently ignored. This is what is mostly wanted
-     * for a logging system - most users will not care about errors in
-     * the logging system, they are more interested in application errors.
-     * You could, however, replace this with a custom handler if you wish.
-     * The record which was being processed is passed in to this method.
+     * encountered during an emit() call.
     */
    handleError(record: LogRecord) {
-        throw new NotImplementedError(
-            'still need to find portable way for stacktracing...'
-        )
+        try {
+            console.error('--- Logging error ---');
+            console.error('Error in handler for record:', record.scope, record.msg);
+        }
+        catch (_) {
+            // silently ignore errors in error handling
+        }
    }

+    get formatter(): Formatter|null { return this._formatter }
    set formatter(fmt: Formatter) { this._formatter = fmt }
 }

+/**
+ * A handler class which writes logging records, appropriately formatted,
+ * to a stream. Note that this class does not close the stream, as
+ * the default stream may be shared.
+ */
+export class StreamHandler extends Handler {
+    protected stream: Writable;
+
+    constructor(stream?: Writable) {
+        super();
+        this.stream = stream ?? DEFAULT_STREAM;
+    }
+
+    emit(record: LogRecord) {
+        try {
+            const msg = this.format(record);
+            this.stream.write(msg);
+        }
+        catch (e) {
+            this.handleError(record);
+        }
+    }
+}
+
+/**
+ * A handler class which writes logging records to the browser console,
+ * mapping log levels to the appropriate console method.
+ *
+ * This is the primary handler for browser environments.
+ */
+export class ConsoleHandler extends Handler {
+    emit(record: LogRecord) {
+        try {
+            const msg = this.format(record);
+
+            if (record.levelno >= ERROR) {
+                console.error(msg);
+            }
+            else if (record.levelno >= WARNING) {
+                console.warn(msg);
+            }
+            else {
+                console.log(msg);
+            }
+        }
+        catch (e) {
+            this.handleError(record);
+        }
+    }
+}
+
 export interface FileHandlerOptions {
    filename: string
    filemode?: string
@ -169,20 +209,121 @@ export interface FileHandlerOptions {
    errors?: string
 }

-/**
- * A handler class which writes logging records, appropriately formatted,
-   to a stream. Note that this class does not close the stream, as
-   sys.stdout or sys.stderr may be used.
- */
-export class StreamHandler extends Handler {
-    constructor(stream?: stream.Writable) {
-        super();
-    }
-}
-
 export class FileHandler extends StreamHandler {
    constructor(options: FileHandlerOptions) {
        super();
+        throw new NotImplementedError(
+            'FileHandler is not available in browser environments. ' +
+            'Use ConsoleHandler or a storage-backed handler instead.'
+        );
+    }
+}
+
+/**
+ * A handler that persists log records to browser localStorage.
+ *
+ * Records are stored as a JSON array of formatted strings under a
+ * configurable key. Log rotation is supported by entry count and/or
+ * byte size to avoid exceeding storage quotas.
+ */
+export interface LocalStorageHandlerOptions {
+    /**
+     * localStorage key to store entries under.
+     * Defaults to 'esm-logging'.
+     */
+    key?: string;
+
+    /**
+     * Maximum number of entries to retain. Oldest entries are discarded
+     * first. Set to 0 for no entry limit. Defaults to 1000.
+     */
+    maxEntries?: number;
+
+    /**
+     * Maximum size in bytes (as measured by the JSON-serialized string
+     * length). Oldest entries are discarded to stay within this limit.
+     * Set to 0 for no byte limit. Defaults to 0.
+     */
+    maxBytes?: number;
+}
+
+export class LocalStorageHandler extends Handler {
+    protected key: string;
+    protected maxEntries: number;
+    protected maxBytes: number;
+
+    constructor(options?: LocalStorageHandlerOptions) {
+        super();
+
+        if (typeof localStorage === 'undefined') {
+            throw new NotImplementedError(
+                'LocalStorageHandler requires a browser environment with localStorage'
+            );
+        }
+
+        this.key = options?.key ?? 'esm-logging';
+        this.maxEntries = options?.maxEntries ?? 1000;
+        this.maxBytes = options?.maxBytes ?? 0;
+    }
+
+    emit(record: LogRecord) {
+        try {
+            const msg = this.format(record);
+            const entries = this.getEntries();
+            entries.push(msg);
+            this._rotate(entries);
+            this._setEntries(entries);
+        }
+        catch (e) {
+            this.handleError(record);
+        }
+    }
+
+    /**
+     * Retrieve all stored log entries.
+     */
+    getEntries(): string[] {
+        try {
+            const data = localStorage.getItem(this.key);
+            return data ? JSON.parse(data) : [];
+        }
+        catch {
+            return [];
+        }
+    }
+
+    /**
+     * Remove all stored log entries.
+     */
+    clearEntries() {
+        localStorage.removeItem(this.key);
+    }
+
+    close() {
+        super.close();
+    }
+
+    /**
+     * Discard oldest entries to stay within maxEntries and maxBytes limits.
+     */
+    protected _rotate(entries: string[]) {
+        if (this.maxEntries > 0) {
+            while (entries.length > this.maxEntries) {
+                entries.shift();
+            }
+        }
+
+        if (this.maxBytes > 0) {
+            while (entries.length > 0) {
+                const serialized = JSON.stringify(entries);
+                if (serialized.length <= this.maxBytes) { break }
+                entries.shift();
+            }
+        }
+    }
+
+    protected _setEntries(entries: string[]) {
+        localStorage.setItem(this.key, JSON.stringify(entries));
    }
 }

@ -191,9 +332,16 @@ export class FileHandler extends StreamHandler {
 * whatever sys.stderr is currently set to rather than the value of
 * sys.stderr at handler construction time.
 */
- export class StderrHandler extends Handler {
-    /**
-     * Initialize the handler.
-     */
+export class StderrHandler extends Handler {
    constructor(level: LogLevel) { super(level) }
+
+    emit(record: LogRecord) {
+        try {
+            const msg = this.format(record);
+            console.error(msg);
+        }
+        catch (e) {
+            this.handleError(record);
+        }
+    }
 }
--- a/src/helper/stream.ts
+++ b/src/helper/stream.ts
@ -1,2 +1,33 @@
+/**
+ * Minimal writable stream interface for browser compatibility.
+ *
+ * This abstracts over Node.js streams and browser console output,
+ * providing a common write target for handlers.
+ */
+export interface Writable {
+    write(data: string): void;
+}

-export type MillisecondsSinceUnixEpoch = number;
+/**
+ * A Writable backed by console.log.
+ */
+export class ConsoleWritable implements Writable {
+    write(data: string): void {
+        console.log(data);
+    }
+}
+
+/**
+ * A Writable backed by console.error (stderr equivalent).
+ */
+export class StderrWritable implements Writable {
+    write(data: string): void {
+        console.error(data);
+    }
+}
+
+/**
+ * Default output stream. Uses console.error to match Python's default
+ * of writing to sys.stderr.
+ */
+export const DEFAULT_STREAM: Writable = new StderrWritable();
--- a/src/index.ts
+++ b/src/index.ts
@ -94,7 +94,7 @@ export * as formatter from './formatter';
 export * as handler from './handler';
 // screw community conventions, whoever came up with the idea of aliasing
 // imports in pascal case, or camel case doesn't seem to care about naming
-// collisions. I'm sticking to snake case as this avoids naming collisions.
+// collisions. I'm sticking to kebab case as this avoids naming collisions.
 export * as log_level from './log-level';
 export * as log_record from './log-record';
 export * as logger from './logger';
--- a/src/log-record.ts
+++ b/src/log-record.ts
@ -48,13 +48,32 @@ export class LogRecord {
    public readonly levelno: LogLevel;
    public readonly levelname: string|LogLevel;
    public readonly scope: string;
+    public readonly name: string;
+    public readonly msg: string;
+    public readonly args: any[]|undefined;
+    public message: string = '';

    public readonly created: MillisecondsSinceUnixEpoch = Date.now();
+    public asctime: string = '';

    constructor(scope: string, options: LogRecordOptions) {
        this.levelno = options.level;
        this.levelname = getLevelName(options.level);
        this.scope = scope;
+        this.name = scope;
+        this.msg = options.msg;
+        this.args = options.args;
+    }
+
+    getMessage(): string {
+        let msg = String(this.msg);
+        if (this.args && this.args.length > 0) {
+            msg = this.args.reduce(
+                (s, arg) => s.replace('%s', String(arg)),
+                msg
+            );
+        }
+        return msg;
    }
 }

--- a/src/logger.ts
+++ b/src/logger.ts
@ -1,8 +1,11 @@
 import {
    LogLevel,
    DEBUG,
-    NOTSET,
+    INFO,
    WARNING,
+    ERROR,
+    CRITICAL,
+    NOTSET,
    checkLevel,
 } from './log-level';
 import { 
@ -108,10 +111,13 @@ export class Logger extends Filterer {

    public set level(level: LogLevel) { this._level = checkLevel(level) }

+    public get manager(): Manager|null { return this._manager }
+
    public set manager(manager: Manager) {
-        if (this.manager) {
+        if (this._manager) {
            throw new ValueError('logger can only be assigned to manager once');
        }
+        this._manager = manager;
    }

    public setLevel(level: LogLevel) {
@ -143,13 +149,17 @@ export class Logger extends Filterer {
    public isEnabledFor(level: LogLevel): boolean {
        if (this.disabled) { return false }

-        if (this.cache[level] === undefined && this.manager && this.manager.disable < level) {
-            return this.cache[level] = (
-                level >= this.getEffectiveLevel()
-            );
+        if (level in this.cache) {
+            return this.cache[level];
        }

-        return this.cache[level] = false;
+        if (this._manager && this._manager.disable >= level) {
+            this.cache[level] = false;
+            return false;
+        }
+
+        this.cache[level] = level >= this.getEffectiveLevel();
+        return this.cache[level];
    }

    /**
@ -166,6 +176,34 @@ export class Logger extends Filterer {
        if (this.isEnabledFor(DEBUG)) { this._log(DEBUG, msg, options) }
    }

+    /**
+     * Log 'msg % args' with severity 'INFO'
+     */
+    public info(msg: string, options?: LogOptions) {
+        if (this.isEnabledFor(INFO)) { this._log(INFO, msg, options) }
+    }
+
+    /**
+     * Log 'msg % args' with severity 'WARNING'
+     */
+    public warning(msg: string, options?: LogOptions) {
+        if (this.isEnabledFor(WARNING)) { this._log(WARNING, msg, options) }
+    }
+
+    /**
+     * Log 'msg % args' with severity 'ERROR'
+     */
+    public error(msg: string, options?: LogOptions) {
+        if (this.isEnabledFor(ERROR)) { this._log(ERROR, msg, options) }
+    }
+
+    /**
+     * Log 'msg % args' with severity 'CRITICAL'
+     */
+    public critical(msg: string, options?: LogOptions) {
+        if (this.isEnabledFor(CRITICAL)) { this._log(CRITICAL, msg, options) }
+    }
+
    /**
     * A factory method which can be overriden in subclasses to create
     * specialized LogRecords.
@ -191,9 +229,9 @@ export class Logger extends Filterer {

                var [k, v] = item;

-                if (['message', 'asctime'].includes(k as string) ||
-                    (rv as {[key: string]: any}).keys().includes(k as string)) {
-                    throw new KeyError('attempt to overwrite ${k} in LogRecord')
+                if (['message', 'asctime'].includes(k) ||
+                    Object.keys(rv).includes(k)) {
+                    throw new KeyError(`attempt to overwrite ${k} in LogRecord`)
                }

                (rv as any)[k] = options.extra![k as string] as any
@ -226,7 +264,8 @@ export class Logger extends Filterer {
            }
        }

-        var record = this.makeRecord(this.scope, level, msg, options)
+        const record = this.makeRecord(this.scope, level, msg, options);
+        this.handle(this.scope, record);
    }

    /**
--- a/src/manager.ts
+++ b/src/manager.ts
@ -22,7 +22,7 @@ var loggerClass = Logger;
 * Placeholder instance
 */
 class Placeholder {
-    protected loggers: Logger[] = [];
+    public loggers: Logger[] = [];

    /**
     * initialize with the specified logger being a child of this placeholder.
@ -71,20 +71,76 @@ export class Manager {
     * up the parent/child references which pointed to the placeholder to now
     * point to the logger.
     */
-    getLogger(scope: string) {
-        var rv: null|Logger = null;
+    getLogger(scope: string): Logger {
+        let rv: Logger;

-        if (typeof scope != 'string') {
+        if (scope in this.loggers) {
+            const existing = this.loggers[scope];

-            rv = this.loggers[scope];
-
-            if (rv instanceof Placeholder) {
-                var ph = rv;
+            if (existing instanceof Placeholder) {
                rv = new (this._loggerClass ?? loggerClass)(scope, NOTSET);
+                rv.manager = this;
+                this.loggers[scope] = rv;
+                this._fixupChildren(existing, rv);
+                this._fixupParents(rv);
            }
            else {
-                rv = new (this._loggerClass ?? loggerClass)(scope, NOTSET);
-                this.loggers[scope] = rv;
+                rv = existing;
+            }
+        }
+        else {
+            rv = new (this._loggerClass ?? loggerClass)(scope, NOTSET);
+            rv.manager = this;
+            this.loggers[scope] = rv;
+            this._fixupParents(rv);
+        }
+
+        return rv;
+    }
+
+    /**
+     * Ensure that there are either loggers or placeholders all the way from
+     * the specified logger to the root of the logger hierarchy.
+     */
+    protected _fixupParents(logger: Logger) {
+        const name = logger.scope;
+        let i = name.lastIndexOf('.');
+        let rv: Logger | null = null;
+
+        while (i > 0 && !rv) {
+            const substr = name.substring(0, i);
+
+            if (!(substr in this.loggers)) {
+                this.loggers[substr] = new Placeholder(logger) as unknown as Logger;
+            }
+            else {
+                const obj = this.loggers[substr];
+
+                if (obj instanceof Placeholder) {
+                    obj.push(logger);
+                }
+                else {
+                    rv = obj;
+                }
+            }
+
+            i = name.lastIndexOf('.', i - 1);
+        }
+
+        (logger as unknown as { parent: Logger }).parent = rv ?? this.root;
+    }
+
+    /**
+     * Ensure that children of the placeholder ph are connected to the
+     * specified logger.
+     */
+    protected _fixupChildren(ph: Placeholder, logger: Logger) {
+        const name = logger.scope;
+
+        for (const c of ph.loggers) {
+            if (c.parent!.scope.substring(0, name.length) !== name) {
+                (logger as unknown as { parent: Logger }).parent = c.parent!;
+                (c as unknown as { parent: Logger }).parent = logger;
            }
        }
    }
@ -115,7 +171,9 @@ export class Manager {
     */
    public clear() {
        Object.values(this.loggers).forEach((logger) => {
-            logger.clear()
+            if (!(logger instanceof Placeholder)) {
+                logger.clear();
+            }
        });
    }
 }
--- a/tests/unit/config.test.ts
+++ b/tests/unit/config.test.ts
@ -0,0 +1,93 @@
+import {expect, jest, test} from '@jest/globals';
+import { basicConfig } from '../../src/config';
+import { MANAGER } from '../../src/manager';
+import { Handler } from '../../src/handler';
+import { LogRecord } from '../../src/log-record';
+import { Formatter } from '../../src/formatter';
+import { DEBUG, WARNING, ERROR } from '../../src/log-level';
+describe('basicConfig', () => {
+    beforeEach(() => {
+        MANAGER.root.handlers.splice(0, MANAGER.root.handlers.length);
+    });
+
+    test('adds a handler to the root logger', () => {
+        basicConfig({});
+        expect(MANAGER.root.handlers.length).toBeGreaterThan(0);
+    });
+
+    test('sets root logger level', () => {
+        basicConfig({ level: DEBUG });
+        expect(MANAGER.root.level).toBe(DEBUG);
+    });
+
+    test('does nothing when handlers already exist and force is false', () => {
+        basicConfig({ level: DEBUG });
+        const handlerCount = MANAGER.root.handlers.length;
+        basicConfig({ level: ERROR });
+        expect(MANAGER.root.handlers.length).toBe(handlerCount);
+        expect(MANAGER.root.level).toBe(DEBUG);
+    });
+
+    test('replaces handlers when force is true', () => {
+        basicConfig({ level: DEBUG });
+        basicConfig({ level: ERROR, force: true });
+        expect(MANAGER.root.level).toBe(ERROR);
+    });
+
+    test('throws on invalid style', () => {
+        expect(() => {
+            basicConfig({ style: 'X' });
+        }).toThrow('style must be one of');
+    });
+
+    test('throws when stream and filename both specified', () => {
+        expect(() => {
+            basicConfig({
+                stream: process.stderr,
+                filename: 'test.log',
+            });
+        }).toThrow('should not be specified together');
+    });
+
+    test('throws when handlers and stream both specified', () => {
+        class TestHandler extends Handler {
+            emit(record: LogRecord) {}
+        }
+        expect(() => {
+            basicConfig({
+                handlers: [new TestHandler()],
+                stream: process.stderr,
+            });
+        }).toThrow('should not be specified together');
+    });
+
+    test('uses provided handlers', () => {
+        class TestHandler extends Handler {
+            emit(record: LogRecord) {}
+        }
+        const handler = new TestHandler();
+        basicConfig({ handlers: [handler] });
+        expect(MANAGER.root.handlers).toContain(handler);
+    });
+
+    test('assigns formatter to handlers without one', () => {
+        class TestHandler extends Handler {
+            emit(record: LogRecord) {}
+        }
+        const handler = new TestHandler();
+        expect(handler.formatter).toBeNull();
+        basicConfig({ handlers: [handler] });
+        expect(handler.formatter).not.toBeNull();
+    });
+
+    test('preserves existing formatter on handlers', () => {
+        class TestHandler extends Handler {
+            emit(record: LogRecord) {}
+        }
+        const handler = new TestHandler();
+        const fmt = new Formatter({ fmt: '%(message)s' });
+        handler.formatter = fmt;
+        basicConfig({ handlers: [handler] });
+        expect(handler.formatter).toBe(fmt);
+    });
+});
--- a/tests/unit/formatter.test.ts
+++ b/tests/unit/formatter.test.ts
@ -0,0 +1,143 @@
+import {expect, jest, test} from '@jest/globals';
+import { Formatter, DEFAULT_FORMATTER } from '../../src/formatter';
+import { LogRecord } from '../../src/log-record';
+import { DEBUG, WARNING, INFO } from '../../src/log-level';
+import { MyError } from '../../src/helper/error';
+
+function makeRecord(level: number, msg: string): LogRecord {
+    return new LogRecord('test.module', { level, msg });
+}
+
+describe('Formatter', () => {
+    describe('constructor', () => {
+        test('uses default format when no options given', () => {
+            const fmt = new Formatter();
+            const record = makeRecord(WARNING, 'hello');
+            const result = fmt.format(record);
+            expect(result).toBe('hello');
+        });
+
+        test('accepts custom format string', () => {
+            const fmt = new Formatter({ fmt: '%(levelname)s - %(message)s' });
+            const record = makeRecord(DEBUG, 'debug msg');
+            expect(fmt.format(record)).toBe('DEBUG - debug msg');
+        });
+
+        test('throws on invalid style', () => {
+            expect(() => new Formatter({ style: '{' })).toThrow('style must be one of');
+        });
+    });
+
+    describe('format', () => {
+        test('substitutes %(name)s with logger scope', () => {
+            const fmt = new Formatter({ fmt: '[%(name)s] %(message)s' });
+            const record = makeRecord(INFO, 'test');
+            expect(fmt.format(record)).toBe('[test.module] test');
+        });
+
+        test('substitutes %(levelno)d with numeric level', () => {
+            const fmt = new Formatter({ fmt: '%(levelno)d: %(message)s' });
+            const record = makeRecord(WARNING, 'warn');
+            expect(fmt.format(record)).toBe('30: warn');
+        });
+
+        test('substitutes %(levelname)s with level name', () => {
+            const fmt = new Formatter({ fmt: '%(levelname)s %(message)s' });
+            const record = makeRecord(DEBUG, 'msg');
+            expect(fmt.format(record)).toBe('DEBUG msg');
+        });
+
+        test('handles multiple placeholders', () => {
+            const fmt = new Formatter({
+                fmt: '%(levelname)s:%(name)s:%(levelno)d:%(message)s'
+            });
+            const record = makeRecord(WARNING, 'multi');
+            expect(fmt.format(record)).toBe('WARNING:test.module:30:multi');
+        });
+
+        test('throws on unknown field', () => {
+            const fmt = new Formatter({ fmt: '%(nonexistent)s' });
+            const record = makeRecord(DEBUG, 'test');
+            expect(() => fmt.format(record)).toThrow('formatting field not found');
+        });
+
+        test('populates asctime when format uses it', () => {
+            const fmt = new Formatter({
+                fmt: '%(asctime)s %(message)s'
+            });
+            const record = makeRecord(INFO, 'timed');
+            const result = fmt.format(record);
+            expect(result).toContain('timed');
+            expect(record.asctime.length).toBeGreaterThan(0);
+        });
+
+        test('does not populate asctime when format does not use it', () => {
+            const fmt = new Formatter({ fmt: '%(message)s' });
+            const record = makeRecord(INFO, 'no time');
+            fmt.format(record);
+            expect(record.asctime).toBe('');
+        });
+    });
+
+    describe('formatTime', () => {
+        test('returns ISO8601-like string by default', () => {
+            const fmt = new Formatter();
+            const record = makeRecord(INFO, 'test');
+            const result = fmt.formatTime(record);
+            expect(result).toMatch(/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}/);
+        });
+
+        test('uses custom datefmt with strftime tokens', () => {
+            const fmt = new Formatter();
+            const record = makeRecord(INFO, 'test');
+            const result = fmt.formatTime(record, '%Y/%m/%d');
+            expect(result).toMatch(/^\d{4}\/\d{2}\/\d{2}$/);
+        });
+    });
+
+    describe('formatError', () => {
+        test('returns stack trace when available', () => {
+            const fmt = new Formatter();
+            const err = new MyError('test error');
+            const result = fmt.formatError(err);
+            expect(result).toContain('test error');
+            expect(result).toContain('\n');
+        });
+
+        test('returns string representation when no stack', () => {
+            const fmt = new Formatter();
+            const err = new MyError('no stack');
+            err.stack = undefined;
+            const result = fmt.formatError(err);
+            expect(result).toContain('no stack');
+        });
+    });
+
+    describe('usesTime', () => {
+        test('returns true when format contains asctime', () => {
+            const fmt = new Formatter({ fmt: '%(asctime)s %(message)s' });
+            expect(fmt.usesTime()).toBe(true);
+        });
+
+        test('returns false when format does not contain asctime', () => {
+            const fmt = new Formatter({ fmt: '%(message)s' });
+            expect(fmt.usesTime()).toBe(false);
+        });
+    });
+});
+
+describe('LogRecord.getMessage', () => {
+    test('returns the message string', () => {
+        const record = makeRecord(INFO, 'plain message');
+        expect(record.getMessage()).toBe('plain message');
+    });
+
+    test('substitutes %s args into message', () => {
+        const record = new LogRecord('test', {
+            level: INFO,
+            msg: 'hello %s, you have %s items',
+            args: ['world', '5'],
+        });
+        expect(record.getMessage()).toBe('hello world, you have 5 items');
+    });
+});
--- a/tests/unit/handler.test.ts
+++ b/tests/unit/handler.test.ts
@ -0,0 +1,211 @@
+import {expect, jest, test} from '@jest/globals';
+import {
+    Handler,
+    StreamHandler,
+    ConsoleHandler,
+    StderrHandler,
+    FileHandler,
+} from '../../src/handler';
+import { Formatter, DEFAULT_FORMATTER } from '../../src/formatter';
+import { LogRecord } from '../../src/log-record';
+import { Writable } from '../../src/helper/stream';
+import { DEBUG, INFO, WARNING, ERROR, CRITICAL, NOTSET } from '../../src/log-level';
+
+function makeRecord(level: number, msg: string): LogRecord {
+    return new LogRecord('test', { level, msg });
+}
+
+describe('Handler', () => {
+    describe('constructor', () => {
+        test('defaults to NOTSET level', () => {
+            const h = new Handler();
+            expect(h.level).toBe(NOTSET);
+        });
+
+        test('accepts a level argument', () => {
+            const h = new Handler(WARNING);
+            expect(h.level).toBe(WARNING);
+        });
+    });
+
+    describe('level setter', () => {
+        test('sets the level without infinite recursion', () => {
+            const h = new Handler();
+            h.level = ERROR;
+            expect(h.level).toBe(ERROR);
+        });
+    });
+
+    describe('formatter', () => {
+        test('getter returns null when no formatter set', () => {
+            const h = new Handler();
+            expect(h.formatter).toBeNull();
+        });
+
+        test('getter returns assigned formatter', () => {
+            const h = new Handler();
+            const fmt = new Formatter();
+            h.formatter = fmt;
+            expect(h.formatter).toBe(fmt);
+        });
+    });
+
+    describe('format', () => {
+        test('uses DEFAULT_FORMATTER when no formatter assigned', () => {
+            const h = new Handler();
+            const record = makeRecord(DEBUG, 'hello');
+            const result = h.format(record);
+            expect(typeof result).toBe('string');
+        });
+
+        test('returns a string', () => {
+            const h = new Handler();
+            const record = makeRecord(WARNING, 'test message');
+            expect(typeof h.format(record)).toBe('string');
+        });
+    });
+
+    describe('emit', () => {
+        test('throws NotImplementedError on base class', () => {
+            const h = new Handler();
+            const record = makeRecord(DEBUG, 'hello');
+            expect(() => h.emit(record)).toThrow('emit must be implemented');
+        });
+    });
+
+    describe('close', () => {
+        test('sets closed to true', () => {
+            const h = new Handler();
+            expect(h.closed).toBe(false);
+            h.close();
+            expect(h.closed).toBe(true);
+        });
+    });
+
+    describe('handleError', () => {
+        test('does not throw', () => {
+            const h = new Handler();
+            const record = makeRecord(DEBUG, 'test');
+            expect(() => h.handleError(record)).not.toThrow();
+        });
+    });
+});
+
+describe('StreamHandler', () => {
+    test('writes formatted output to the stream', () => {
+        const written: string[] = [];
+        const stream: Writable = { write: (data: string) => { written.push(data) } };
+        const h = new StreamHandler(stream);
+        const record = makeRecord(WARNING, 'stream test');
+        h.emit(record);
+        expect(written.length).toBe(1);
+        expect(written[0]).toContain('stream test');
+    });
+
+    test('uses default stream when none provided', () => {
+        const h = new StreamHandler();
+        const record = makeRecord(DEBUG, 'default stream');
+        expect(() => h.emit(record)).not.toThrow();
+    });
+
+    test('calls handleError on emit failure', () => {
+        const stream: Writable = {
+            write: () => { throw new Error('write failed') }
+        };
+        const h = new StreamHandler(stream);
+        const record = makeRecord(DEBUG, 'fail');
+        expect(() => h.emit(record)).not.toThrow();
+    });
+});
+
+describe('ConsoleHandler', () => {
+    let origLog: typeof console.log;
+    let origWarn: typeof console.warn;
+    let origError: typeof console.error;
+    let logged: string[];
+    let warned: string[];
+    let errored: string[];
+
+    beforeEach(() => {
+        logged = [];
+        warned = [];
+        errored = [];
+        origLog = console.log;
+        origWarn = console.warn;
+        origError = console.error;
+        console.log = (...args: any[]) => { logged.push(args.join(' ')) };
+        console.warn = (...args: any[]) => { warned.push(args.join(' ')) };
+        console.error = (...args: any[]) => { errored.push(args.join(' ')) };
+    });
+
+    afterEach(() => {
+        console.log = origLog;
+        console.warn = origWarn;
+        console.error = origError;
+    });
+
+    test('uses console.error for ERROR level', () => {
+        const h = new ConsoleHandler();
+        h.emit(makeRecord(ERROR, 'error msg'));
+        expect(errored.length).toBe(1);
+        expect(errored[0]).toContain('error msg');
+    });
+
+    test('uses console.error for CRITICAL level', () => {
+        const h = new ConsoleHandler();
+        h.emit(makeRecord(CRITICAL, 'critical msg'));
+        expect(errored.length).toBe(1);
+        expect(errored[0]).toContain('critical msg');
+    });
+
+    test('uses console.warn for WARNING level', () => {
+        const h = new ConsoleHandler();
+        h.emit(makeRecord(WARNING, 'warn msg'));
+        expect(warned.length).toBe(1);
+        expect(warned[0]).toContain('warn msg');
+    });
+
+    test('uses console.log for INFO level', () => {
+        const h = new ConsoleHandler();
+        h.emit(makeRecord(INFO, 'info msg'));
+        expect(logged.length).toBe(1);
+        expect(logged[0]).toContain('info msg');
+    });
+
+    test('uses console.log for DEBUG level', () => {
+        const h = new ConsoleHandler();
+        h.emit(makeRecord(DEBUG, 'debug msg'));
+        expect(logged.length).toBe(1);
+        expect(logged[0]).toContain('debug msg');
+    });
+});
+
+describe('StderrHandler', () => {
+    test('accepts a level', () => {
+        const h = new StderrHandler(ERROR);
+        expect(h.level).toBe(ERROR);
+    });
+
+    test('emits via console.error', () => {
+        const errored: string[] = [];
+        const origError = console.error;
+        console.error = (...args: any[]) => { errored.push(args.join(' ')) };
+        try {
+            const h = new StderrHandler(DEBUG);
+            h.emit(makeRecord(WARNING, 'stderr test'));
+            expect(errored.length).toBe(1);
+            expect(errored[0]).toContain('stderr test');
+        }
+        finally {
+            console.error = origError;
+        }
+    });
+});
+
+describe('FileHandler', () => {
+    test('throws NotImplementedError on construction', () => {
+        expect(() => new FileHandler({
+            filename: 'test.log'
+        })).toThrow('not available in browser');
+    });
+});
--- a/tests/unit/local-storage-handler.test.ts
+++ b/tests/unit/local-storage-handler.test.ts
@ -0,0 +1,158 @@
+import {expect, jest, test, beforeEach, afterEach} from '@jest/globals';
+import { LocalStorageHandler } from '../../src/handler';
+import { LogRecord } from '../../src/log-record';
+import { DEBUG, WARNING, ERROR } from '../../src/log-level';
+
+// mock localStorage for Node/Jest environment
+const store: {[key: string]: string} = {};
+const localStorageMock = {
+    getItem: (key: string): string | null => store[key] ?? null,
+    setItem: (key: string, value: string) => { store[key] = value },
+    removeItem: (key: string) => { delete store[key] },
+};
+
+function clearStore() {
+    for (const key of Object.keys(store)) { delete store[key] }
+}
+
+function makeRecord(level: number, msg: string): LogRecord {
+    return new LogRecord('test', { level, msg });
+}
+
+beforeEach(() => {
+    clearStore();
+    (globalThis as any).localStorage = localStorageMock;
+});
+
+afterEach(() => {
+    clearStore();
+    delete (globalThis as any).localStorage;
+});
+
+describe('LocalStorageHandler', () => {
+    describe('constructor', () => {
+        test('uses default key and limits', () => {
+            const h = new LocalStorageHandler();
+            expect(h.getEntries()).toEqual([]);
+        });
+
+        test('throws when localStorage is unavailable', () => {
+            delete (globalThis as any).localStorage;
+            expect(() => new LocalStorageHandler()).toThrow(
+                'requires a browser environment'
+            );
+        });
+
+        test('accepts custom options', () => {
+            const h = new LocalStorageHandler({
+                key: 'custom-log',
+                maxEntries: 50,
+                maxBytes: 4096,
+            });
+            h.emit(makeRecord(DEBUG, 'test'));
+            expect(store['custom-log']).toBeDefined();
+            expect(store['esm-logging']).toBeUndefined();
+        });
+    });
+
+    describe('emit', () => {
+        test('stores formatted log entry', () => {
+            const h = new LocalStorageHandler();
+            h.emit(makeRecord(WARNING, 'hello'));
+            const entries = h.getEntries();
+            expect(entries.length).toBe(1);
+            expect(entries[0]).toContain('hello');
+        });
+
+        test('appends multiple entries', () => {
+            const h = new LocalStorageHandler();
+            h.emit(makeRecord(DEBUG, 'first'));
+            h.emit(makeRecord(DEBUG, 'second'));
+            h.emit(makeRecord(DEBUG, 'third'));
+            expect(h.getEntries().length).toBe(3);
+        });
+
+        test('persists across handler instances with same key', () => {
+            const h1 = new LocalStorageHandler({ key: 'shared' });
+            h1.emit(makeRecord(DEBUG, 'from h1'));
+
+            const h2 = new LocalStorageHandler({ key: 'shared' });
+            const entries = h2.getEntries();
+            expect(entries.length).toBe(1);
+            expect(entries[0]).toContain('from h1');
+        });
+    });
+
+    describe('rotation by entry count', () => {
+        test('discards oldest entries when maxEntries exceeded', () => {
+            const h = new LocalStorageHandler({ maxEntries: 3 });
+            h.emit(makeRecord(DEBUG, 'msg-1'));
+            h.emit(makeRecord(DEBUG, 'msg-2'));
+            h.emit(makeRecord(DEBUG, 'msg-3'));
+            h.emit(makeRecord(DEBUG, 'msg-4'));
+
+            const entries = h.getEntries();
+            expect(entries.length).toBe(3);
+            expect(entries[0]).toContain('msg-2');
+            expect(entries[2]).toContain('msg-4');
+        });
+
+        test('maxEntries of 1 keeps only the latest', () => {
+            const h = new LocalStorageHandler({ maxEntries: 1 });
+            h.emit(makeRecord(DEBUG, 'old'));
+            h.emit(makeRecord(DEBUG, 'new'));
+
+            const entries = h.getEntries();
+            expect(entries.length).toBe(1);
+            expect(entries[0]).toContain('new');
+        });
+    });
+
+    describe('rotation by byte size', () => {
+        test('discards oldest entries when maxBytes exceeded', () => {
+            const h = new LocalStorageHandler({ maxEntries: 0, maxBytes: 100 });
+            // emit entries until we exceed the limit
+            for (let i = 0; i < 20; i++) {
+                h.emit(makeRecord(DEBUG, `message-${i}`));
+            }
+
+            const entries = h.getEntries();
+            const serialized = JSON.stringify(entries);
+            expect(serialized.length).toBeLessThanOrEqual(100);
+            expect(entries.length).toBeGreaterThan(0);
+        });
+    });
+
+    describe('getEntries', () => {
+        test('returns empty array when no entries', () => {
+            const h = new LocalStorageHandler();
+            expect(h.getEntries()).toEqual([]);
+        });
+
+        test('returns empty array on corrupt data', () => {
+            store['esm-logging'] = 'not valid json{{{';
+            const h = new LocalStorageHandler();
+            expect(h.getEntries()).toEqual([]);
+        });
+    });
+
+    describe('clearEntries', () => {
+        test('removes all stored entries', () => {
+            const h = new LocalStorageHandler();
+            h.emit(makeRecord(DEBUG, 'to be cleared'));
+            expect(h.getEntries().length).toBe(1);
+
+            h.clearEntries();
+            expect(h.getEntries()).toEqual([]);
+        });
+    });
+
+    describe('close', () => {
+        test('sets closed to true', () => {
+            const h = new LocalStorageHandler();
+            expect(h.closed).toBe(false);
+            h.close();
+            expect(h.closed).toBe(true);
+        });
+    });
+});
--- a/tests/unit/log-level.test.ts
+++ b/tests/unit/log-level.test.ts
@ -1,5 +1,5 @@
 import {expect, jest, test} from '@jest/globals';
-import * as log_level from '../src/log-level';
+import * as log_level from '../../src/log-level';

 describe('Logger', () => {
    it('can be instantiated', () => {
--- a/tests/unit/logger.test.ts
+++ b/tests/unit/logger.test.ts
@ -0,0 +1,209 @@
+import {expect, jest, test} from '@jest/globals';
+import { Logger, RootLogger, ROOT } from '../../src/logger';
+import { Handler } from '../../src/handler';
+import { LogRecord } from '../../src/log-record';
+import { Formatter } from '../../src/formatter';
+import { Manager } from '../../src/manager';
+import {
+    DEBUG,
+    INFO,
+    WARNING,
+    ERROR,
+    CRITICAL,
+    NOTSET,
+} from '../../src/log-level';
+import { MyError } from '../../src/helper/error';
+
+describe('Logger', () => {
+    describe('constructor', () => {
+        test('sets scope and default level', () => {
+            const logger = new Logger('test');
+            expect(logger.scope).toBe('test');
+            expect(logger.level).toBe(NOTSET);
+        });
+
+        test('accepts explicit level', () => {
+            const logger = new Logger('test', WARNING);
+            expect(logger.level).toBe(WARNING);
+        });
+    });
+
+    describe('setLevel', () => {
+        test('changes the level', () => {
+            const logger = new Logger('test');
+            logger.setLevel(ERROR);
+            expect(logger.level).toBe(ERROR);
+        });
+    });
+
+    describe('getEffectiveLevel', () => {
+        test('returns own level when set', () => {
+            const logger = new Logger('test', WARNING);
+            expect(logger.getEffectiveLevel()).toBe(WARNING);
+        });
+
+        test('returns NOTSET when no level set and no parent', () => {
+            const logger = new Logger('test');
+            expect(logger.getEffectiveLevel()).toBe(NOTSET);
+        });
+    });
+
+    describe('isEnabledFor', () => {
+        test('returns true when level meets effective level', () => {
+            const logger = new Logger('test', DEBUG);
+            expect(logger.isEnabledFor(WARNING)).toBe(true);
+            expect(logger.isEnabledFor(DEBUG)).toBe(true);
+        });
+
+        test('returns false when level is below effective level', () => {
+            const logger = new Logger('test', WARNING);
+            expect(logger.isEnabledFor(DEBUG)).toBe(false);
+            expect(logger.isEnabledFor(INFO)).toBe(false);
+        });
+
+        test('caches results for repeated calls', () => {
+            const logger = new Logger('test', WARNING);
+            const first = logger.isEnabledFor(DEBUG);
+            const second = logger.isEnabledFor(DEBUG);
+            expect(first).toBe(second);
+        });
+
+        test('respects manager disable level', () => {
+            const root = new RootLogger(WARNING);
+            const manager = new Manager(root);
+            const logger = manager.getLogger('test');
+            logger.setLevel(DEBUG);
+            logger.manager = manager;
+            manager.disable = ERROR;
+            logger.clear();
+            expect(logger.isEnabledFor(DEBUG)).toBe(false);
+            expect(logger.isEnabledFor(WARNING)).toBe(false);
+            expect(logger.isEnabledFor(CRITICAL)).toBe(true);
+        });
+    });
+
+    describe('manager property', () => {
+        test('starts as null', () => {
+            const logger = new Logger('test');
+            expect(logger.manager).toBeNull();
+        });
+
+        test('can be assigned once', () => {
+            const logger = new Logger('test');
+            const root = new RootLogger(WARNING);
+            const manager = new Manager(root);
+            logger.manager = manager;
+            expect(logger.manager).toBe(manager);
+        });
+
+        test('throws on second assignment', () => {
+            const logger = new Logger('test');
+            const root = new RootLogger(WARNING);
+            const manager = new Manager(root);
+            logger.manager = manager;
+            expect(() => { logger.manager = manager }).toThrow('logger can only be assigned to manager once');
+        });
+    });
+
+    describe('addHandler / removeHandler', () => {
+        test('adds and removes handlers', () => {
+            const logger = new Logger('test');
+            const handler = new Handler(DEBUG);
+            expect(logger.handlers.length).toBe(0);
+            logger.addHandler(handler);
+            expect(logger.handlers.length).toBe(1);
+            logger.removeHandler(handler);
+        });
+
+        test('does not add duplicate handlers', () => {
+            const logger = new Logger('test');
+            const handler = new Handler(DEBUG);
+            logger.addHandler(handler);
+            logger.addHandler(handler);
+            expect(logger.handlers.length).toBe(1);
+        });
+    });
+
+    describe('level methods', () => {
+        let logger: Logger;
+        let emitted: LogRecord[];
+
+        class TestHandler extends Handler {
+            emit(record: LogRecord) { emitted.push(record) }
+        }
+
+        beforeEach(() => {
+            logger = new Logger('test', DEBUG);
+            emitted = [];
+            logger.addHandler(new TestHandler(DEBUG));
+        });
+
+        test('debug emits at DEBUG level', () => {
+            logger.debug('msg');
+            expect(emitted.length).toBe(1);
+            expect(emitted[0].levelno).toBe(DEBUG);
+        });
+
+        test('info emits at INFO level', () => {
+            logger.info('msg');
+            expect(emitted.length).toBe(1);
+            expect(emitted[0].levelno).toBe(INFO);
+        });
+
+        test('warning emits at WARNING level', () => {
+            logger.warning('msg');
+            expect(emitted.length).toBe(1);
+            expect(emitted[0].levelno).toBe(WARNING);
+        });
+
+        test('error emits at ERROR level', () => {
+            logger.error('msg');
+            expect(emitted.length).toBe(1);
+            expect(emitted[0].levelno).toBe(ERROR);
+        });
+
+        test('critical emits at CRITICAL level', () => {
+            logger.critical('msg');
+            expect(emitted.length).toBe(1);
+            expect(emitted[0].levelno).toBe(CRITICAL);
+        });
+
+        test('level methods respect effective level', () => {
+            logger.setLevel(ERROR);
+            logger.clear();
+            logger.debug('no');
+            logger.info('no');
+            logger.warning('no');
+            expect(emitted.length).toBe(0);
+            logger.error('yes');
+            logger.critical('yes');
+            expect(emitted.length).toBe(2);
+        });
+    });
+
+    describe('makeRecord', () => {
+        test('throws KeyError when extra overwrites existing LogRecord key', () => {
+            const logger = new Logger('test', DEBUG);
+            expect(() => {
+                logger.debug('test', {
+                    excInfo: null,
+                    extra: { scope: 'override' },
+                    stackInfo: false,
+                    stackLevel: 1,
+                });
+            }).toThrow('attempt to overwrite scope in LogRecord');
+        });
+    });
+});
+
+describe('RootLogger', () => {
+    test('has scope "root"', () => {
+        const root = new RootLogger(WARNING);
+        expect(root.scope).toBe('root');
+    });
+
+    test('accepts a level', () => {
+        const root = new RootLogger(ERROR);
+        expect(root.level).toBe(ERROR);
+    });
+});
--- a/tests/unit/manager.test.ts
+++ b/tests/unit/manager.test.ts
@ -0,0 +1,209 @@
+import {expect, jest, test} from '@jest/globals';
+import { Manager } from '../../src/manager';
+import { Logger, RootLogger } from '../../src/logger';
+import { Handler } from '../../src/handler';
+import { LogRecord } from '../../src/log-record';
+import { WARNING, DEBUG, INFO, NOTSET } from '../../src/log-level';
+
+function makeManager(): Manager {
+    return new Manager(new RootLogger(WARNING));
+}
+
+describe('Manager', () => {
+    describe('constructor', () => {
+        test('stores the root logger', () => {
+            const root = new RootLogger(WARNING);
+            const manager = new Manager(root);
+            expect(manager.root).toBe(root);
+        });
+    });
+
+    describe('getLogger', () => {
+        test('returns a Logger instance', () => {
+            const manager = makeManager();
+            const logger = manager.getLogger('app');
+            expect(logger).toBeInstanceOf(Logger);
+            expect(logger.scope).toBe('app');
+        });
+
+        test('returns the same logger for the same scope', () => {
+            const manager = makeManager();
+            const a = manager.getLogger('app');
+            const b = manager.getLogger('app');
+            expect(a).toBe(b);
+        });
+
+        test('returns different loggers for different scopes', () => {
+            const manager = makeManager();
+            const a = manager.getLogger('app');
+            const b = manager.getLogger('lib');
+            expect(a).not.toBe(b);
+        });
+
+        test('sets parent to root for top-level loggers', () => {
+            const manager = makeManager();
+            const logger = manager.getLogger('app');
+            expect(logger.parent).toBe(manager.root);
+        });
+
+        test('sets parent to existing parent logger', () => {
+            const manager = makeManager();
+            const parent = manager.getLogger('app');
+            const child = manager.getLogger('app.module');
+            expect(child.parent).toBe(parent);
+        });
+
+        test('establishes hierarchy for deeply nested loggers', () => {
+            const manager = makeManager();
+            const top = manager.getLogger('a');
+            const mid = manager.getLogger('a.b');
+            const leaf = manager.getLogger('a.b.c');
+            expect(leaf.parent).toBe(mid);
+            expect(mid.parent).toBe(top);
+            expect(top.parent).toBe(manager.root);
+        });
+
+        test('creates placeholders for intermediate loggers', () => {
+            const manager = makeManager();
+            const leaf = manager.getLogger('a.b.c');
+            expect(leaf.parent).toBe(manager.root);
+
+            const mid = manager.getLogger('a.b');
+            expect(leaf.parent).toBe(mid);
+            expect(mid.parent).toBe(manager.root);
+        });
+
+        test('fixes up children when intermediate logger is created', () => {
+            const manager = makeManager();
+            const leaf = manager.getLogger('a.b.c');
+            const top = manager.getLogger('a');
+
+            expect(top.parent).toBe(manager.root);
+
+            const mid = manager.getLogger('a.b');
+            expect(leaf.parent).toBe(mid);
+        });
+    });
+
+    describe('disable', () => {
+        test('defaults to 0', () => {
+            const manager = makeManager();
+            expect(manager.disable).toBe(0);
+        });
+
+        test('can be set to a level', () => {
+            const manager = makeManager();
+            manager.disable = WARNING;
+            expect(manager.disable).toBe(WARNING);
+        });
+    });
+
+    describe('loggerClass', () => {
+        test('accepts Logger subclass', () => {
+            const manager = makeManager();
+            class CustomLogger extends Logger {}
+            expect(() => { manager.loggerClass = CustomLogger as any }).not.toThrow();
+        });
+
+        test('rejects non-Logger class', () => {
+            const manager = makeManager();
+            class NotALogger {}
+            expect(() => {
+                manager.loggerClass = NotALogger as any;
+            }).toThrow(TypeError);
+        });
+
+        test('accepts Logger itself', () => {
+            const manager = makeManager();
+            expect(() => { manager.loggerClass = Logger as any }).not.toThrow();
+        });
+    });
+
+    describe('getLogger - manager assignment', () => {
+        test('sets manager on newly created loggers', () => {
+            const manager = makeManager();
+            const logger = manager.getLogger('app');
+            expect(logger.manager).toBe(manager);
+        });
+
+        test('sets manager on loggers created from placeholders', () => {
+            const manager = makeManager();
+            manager.getLogger('a.b.c');
+            const mid = manager.getLogger('a.b');
+            expect(mid.manager).toBe(manager);
+        });
+
+        test('isEnabledFor respects manager.disable via getLogger', () => {
+            const manager = makeManager();
+            const logger = manager.getLogger('app');
+            logger.setLevel(DEBUG);
+
+            expect(logger.isEnabledFor(DEBUG)).toBe(true);
+
+            manager.disable = WARNING;
+            logger.clear();
+
+            expect(logger.isEnabledFor(DEBUG)).toBe(false);
+            expect(logger.isEnabledFor(WARNING)).toBe(false);
+        });
+    });
+
+    describe('propagation through hierarchy', () => {
+        test('child logger propagates records to parent handler', () => {
+            const manager = makeManager();
+            const parent = manager.getLogger('app');
+            const child = manager.getLogger('app.module');
+
+            parent.setLevel(DEBUG);
+            child.setLevel(DEBUG);
+
+            const emitted: string[] = [];
+            const handler = new (class extends Handler {
+                emit(record: LogRecord) {
+                    emitted.push(record.msg);
+                }
+            })(DEBUG);
+
+            parent.addHandler(handler);
+            child.info('propagated message');
+
+            expect(emitted).toContain('propagated message');
+        });
+
+        test('child does not propagate to unrelated logger', () => {
+            const manager = makeManager();
+            const unrelated = manager.getLogger('other');
+            const child = manager.getLogger('app.module');
+
+            unrelated.setLevel(DEBUG);
+            child.setLevel(DEBUG);
+
+            const emitted: string[] = [];
+            const handler = new (class extends Handler {
+                emit(record: LogRecord) {
+                    emitted.push(record.msg);
+                }
+            })(DEBUG);
+
+            unrelated.addHandler(handler);
+            child.info('should not reach');
+
+            expect(emitted).not.toContain('should not reach');
+        });
+    });
+
+    describe('clear', () => {
+        test('clears logger caches', () => {
+            const manager = makeManager();
+            const logger = manager.getLogger('test');
+            logger.isEnabledFor(DEBUG);
+            manager.clear();
+        });
+
+        test('does not throw when placeholders exist', () => {
+            const manager = makeManager();
+            manager.getLogger('a.b.c');
+            expect(() => manager.clear()).not.toThrow();
+        });
+    });
+});
--- a/vendor/tiara-gitflow-spec
+++ b/vendor/tiara-gitflow-spec
@ -0,0 +1 @@
+Subproject commit ee93479edce1da28f4abf68a362427f8d3134f80
Author	SHA1	Message	Date
Tiara Rodney	34be2f8395	Merge branch 'feature/13' into dev	2026-03-14 05:02:56 +01:00
Tiara Rodney	5b29c67d0d	todo(13): done	2026-03-14 05:02:55 +01:00
Tiara Rodney	37fd6194c7	test(handler): add tests for LocalStorageHandler	2026-03-14 04:57:32 +01:00
Tiara Rodney	6fd8c22ceb	feat(handler): implement LocalStorageHandler with rotation	2026-03-14 04:55:37 +01:00
Tiara Rodney	7479931714	todo(13): in-progress	2026-03-14 04:39:24 +01:00
Tiara Rodney	768ff9263d	Merge branch 'feature/10' into dev	2026-03-14 04:34:13 +01:00
Tiara Rodney	b254922d3c	todo(10): done	2026-03-14 04:34:08 +01:00
Tiara Rodney	1a74f2afa4	docs: add user guide, cookbook, and rewrite README	2026-03-14 04:33:53 +01:00
Tiara Rodney	741b959820	todo(10): in-progress	2026-03-14 02:34:31 +01:00
Tiara Rodney	e50fccff8f	Merge branch 'feature/9' into dev	2026-03-14 02:32:40 +01:00
Tiara Rodney	743e8ffc3b	todo(9): done	2026-03-14 02:32:35 +01:00
Tiara Rodney	5022a1e0bc	test(manager): add tests for manager assignment and propagation	2026-03-14 02:32:20 +01:00
Tiara Rodney	94c7d4a1da	feat(manager): set manager on created loggers, fix clear for placeholders getLogger() now assigns manager on newly created loggers so isEnabledFor can check manager.disable. When replacing a Placeholder, _fixupParents is also called to establish the parent chain. clear() skips Placeholder entries that lack a clear method.	2026-03-14 00:23:09 +01:00
Tiara Rodney	cfda9902f7	todo(9): in-progress Set manager on loggers created by getLogger(), verify propagation works end-to-end through the hierarchy.	2026-03-14 00:11:36 +01:00
Tiara Rodney	1d5ded82ba	Merge branch 'feature/8' into dev	2026-03-14 00:00:50 +01:00
Tiara Rodney	672b692013	todo(8): done Added browser-compatible Writable interface with ConsoleWritable and StderrWritable implementations. StreamHandler.emit() writes to a Writable stream. ConsoleHandler maps levels to console.warn/error/log. StderrHandler emits via console.error. FileHandler throws on construction in browser. Handler.handleError() logs diagnostics. Writable interface designed for extensibility (issue 13).	2026-03-14 00:00:50 +01:00
Tiara Rodney	216d2b5892	test(handler): add tests for StreamHandler, ConsoleHandler, StderrHandler Cover StreamHandler emit to custom Writable, default stream fallback, and error handling on write failure. Cover ConsoleHandler level-to- method mapping (error/warn/log). Cover StderrHandler console.error output. Cover FileHandler browser rejection. Cover Handler base class handleError not throwing.	2026-03-14 00:00:34 +01:00
Tiara Rodney	3a6332a855	feat(handler): implement StreamHandler, ConsoleHandler, StderrHandler emit StreamHandler.emit() writes formatted output to a Writable stream. ConsoleHandler maps log levels to console.warn/error/log. StderrHandler emits via console.error. handleError() logs diagnostics instead of throwing. FileHandler throws NotImplementedError on construction. Removed Node.js stream import and conditional require() block.	2026-03-13 23:57:37 +01:00
Tiara Rodney	e6b7f02166	feat(helper/stream): add browser-compatible Writable interface Define Writable interface, ConsoleWritable (console.log), and StderrWritable (console.error) as browser-safe stream abstractions. Export DEFAULT_STREAM backed by StderrWritable to match Python's sys.stderr default.	2026-03-13 23:29:09 +01:00
Tiara Rodney	c297bb4499	todo(8): in-progress Implement StreamHandler.emit(), ConsoleHandler for browser console API, and a browser-compatible stream abstraction. Design handler base with issue 13 (localStorage handler) in mind.	2026-03-13 23:27:50 +01:00
Tiara Rodney	1cab520ba1	Merge branch 'feature/7' into dev	2026-03-13 23:26:40 +01:00
Tiara Rodney	67803747c4	todo(7): done Implemented %-style field substitution in PercentFormatterStyle, JS Date-based formatTime with strftime token support and ISO8601 fallback, Error.stack-based formatError, and LogRecord.getMessage. Added message, name, msg, args fields to LogRecord.	2026-03-13 23:26:39 +01:00
Tiara Rodney	3422cfb799	test(formatter): add tests for formatting, formatTime, formatError Cover %-style substitution with %(name)s, %(levelno)d, %(levelname)s, multiple placeholders, unknown field errors, asctime population, ISO8601 and custom datefmt time formatting, Error.stack formatting, usesTime detection, and LogRecord.getMessage with %s arg substitution.	2026-03-13 23:22:10 +01:00
Tiara Rodney	7b9e88ef59	feat(formatter): implement %-style formatting, formatTime, formatError PercentFormatterStyle._format() now performs %(key)s/d/f substitution against LogRecord attributes. Formatter.format() sets record.message via getMessage() and conditionally calls formatTime() for asctime. formatTime() uses JS Date with strftime-style tokens (%Y,%m,%d,%H, %M,%S) or ISO8601 fallback. formatError() returns Error.stack. BASIC_FORMAT updated to use %(levelname)s. Fixed datefmt type in config.ts.	2026-03-13 23:14:49 +01:00
Tiara Rodney	c0ced4cda2	feat(log-record): add message, name, msg, args fields and getMessage	2026-03-13 23:09:50 +01:00
Tiara Rodney	3dce9422ae	todo(7): in-progress Implement PercentFormatterStyle._format() with %-style field substitution, Formatter.formatTime() using JS Date/Intl, and Formatter.formatError() using Error.stack. Add datetime helpers.	2026-03-13 23:05:33 +01:00
Tiara Rodney	3f424137ac	chore: add roadmap issues 10-13 Add issues for documentation, async support, OCSF formatter, and browser local storage handler from the README roadmap.	2026-03-13 23:02:46 +01:00
Tiara Rodney	2bdcb17ee6	Merge branch 'feature/6' into dev	2026-03-13 22:56:16 +01:00
Tiara Rodney	fcfbd36153	todo(6): done Added info(), warning(), error(), and critical() methods to Logger, each gated by isEnabledFor(). All level methods tested including effective level filtering.	2026-03-13 22:56:15 +01:00
Tiara Rodney	d95c8d37da	test(logger): add tests for info, warning, error, and critical methods	2026-03-13 22:56:01 +01:00
Tiara Rodney	50df6b4c37	feat(logger): add info, warning, error, and critical methods	2026-03-13 22:55:17 +01:00
Tiara Rodney	7ef841ac43	todo(6): in-progress Add info(), warning(), error(), and critical() methods to Logger.	2026-03-13 22:53:09 +01:00
Tiara Rodney	72b92af5aa	Merge branch 'bugfix/5' into dev	2026-03-13 22:50:42 +01:00
Tiara Rodney	6e82574723	todo(5): done Fixed logic bugs across manager, config, logger, handler, and formatter modules. Manager.getLogger() now correctly creates and returns loggers with hierarchy setup. Config.basicConfig() reads the correct option fields and has proper control flow. Logger isEnabledFor() caches correctly, _log() calls handle(), makeRecord() uses Object.keys(). Handler has working formatter getter, format() returns a string, and level setter no longer recurses. Formatter has a format() method. Added unit tests for all four modules.	2026-03-13 22:50:37 +01:00
Tiara Rodney	3b6b116b00	test: add unit tests for handler, logger, manager, and config Cover Handler property accessors, format delegation, emit contract, and close lifecycle. Cover Logger level methods, isEnabledFor caching, manager property assignment, handler management, debug invocation, and makeRecord extra key collision. Cover Manager getLogger hierarchy setup, placeholder fixup, disable level, and loggerClass validation. Cover basicConfig option handling, force flag, mutual exclusion of stream/filename/handlers, and formatter assignment.	2026-03-13 22:49:12 +01:00
Tiara Rodney	0b87f5516a	fix(formatter,manager): add Formatter.format(), fix Placeholder access Add format() method to Formatter class to delegate to the style's format method. Change Placeholder.loggers to public so Manager can access it for hierarchy fixup.	2026-03-13 22:42:52 +01:00
Tiara Rodney	9fed1ffe6b	fix(config): correct basicConfig option assignments and control flow Fix dateformat and style variables reading from wrong option fields (filemode instead of datefmt/style). Restructure control flow to match CPython logic: early return when handlers exist and force is not set, proper mutual exclusion of stream/filename/handlers args. Remove unreachable code block.	2026-03-13 22:41:29 +01:00
Tiara Rodney	e76d8fb77b	fix(logger): fix isEnabledFor, _log, makeRecord, and manager property Fix isEnabledFor() to correctly cache and return level check results instead of always caching false. Fix _log() to call handle() after creating the LogRecord. Fix makeRecord() to use Object.keys() and template literal. Add manager getter and fix setter to actually assign the value.	2026-03-13 22:40:46 +01:00
Tiara Rodney	340b31bc50	fix(handler): add formatter getter, fix format() return, fix level setter Add missing getter for formatter property. Fix format() to return the formatted string instead of discarding it. Fix level setter to assign to _level instead of recursing infinitely.	2026-03-13 22:40:05 +01:00
Tiara Rodney	03e3641e03	fix(manager): correct getLogger and implement hierarchy setup Fix inverted type check in getLogger() and add missing return statement. Implement _fixupParents() and _fixupChildren() to establish parent-child logger relationships based on dot-separated scope names.	2026-03-13 22:39:35 +01:00
Tiara Rodney	df0126693e	todo(5): in-progress Fix logic bugs across manager, config, logger, and handler modules. Manager.getLogger() has inverted type check and missing return. Config.basicConfig() assigns wrong option fields. Logger.isEnabledFor() always caches false, _log() never calls handle(). Handler.format() missing return and formatter getter.	2026-03-13 22:39:02 +01:00
Tiara Rodney	04e9768e89	chore: convert TODO to MIME TODO format and add issues 5-9	2026-03-13 22:38:48 +01:00
Tiara Rodney	25ec89c3b4	fix: correct jest roots and test import path	2026-03-13 22:38:41 +01:00
Tiara Rodney	0cea450c0a	chore: add eslint with typescript-eslint, align package.json scripts	2026-03-13 22:38:36 +01:00
Tiara Rodney	b7c6937219	chore: add tiara-gitflow-spec as vendor submodule	2026-03-13 22:38:27 +01:00
Rodney, Tiara	31f2d6e6f9	chore: move existing tests to sub-directory introducing sub-directories for each type of tests, so that they're easier to seperate.	2025-05-01 22:50:34 +02:00
Rodney, Tiara	e6beeec594	chore: update typedoc	2025-05-01 22:50:34 +02:00
Rodney, Tiara	b50586db8f	test(log_level): refactor	2025-05-01 22:50:34 +02:00
Rodney, Tiara	bcb65bfec5	chore: fix package namespacing	2025-05-01 22:50:33 +02:00
Rodney, Tiara	f069a0f2e4	refactor(src): introduce submodules	2025-05-01 22:50:33 +02:00
Rodney, Tiara	ab4ef2baab	doc(README): init rudimentary README	2025-05-01 22:50:33 +02:00
Rodney, Tiara	9f4d9336d2	style(ci): add commands for removing test-reports Bitbucket Pipelines has some weird default behavior on how artifacts are archived and JUnit test-reports are parsed on every subsequent run, if the output was once an artifact. It's confusing to look at via the dashboard, hence I'm adding an override to remove them beforehand.	2025-05-01 22:50:33 +02:00
Rodney, Tiara	f45e75aa50	to-do(4): in-progress	2025-05-01 22:50:14 +02:00
Rodney, Tiara	07b1228ac0	to-do(4): open	2025-05-01 22:49:51 +02:00
Rodney, Tiara	72248008b9	to-do(3): in-progress	2025-05-01 22:27:00 +02:00
Rodney, Tiara	f38f62f53e	todo(3): open	2025-05-01 22:26:30 +02:00
Rodney, Tiara	fcf45f22a3	todo(1): in-progress	2025-05-01 17:49:34 +02:00
Rodney, Tiara	15e4a5f0e1	doc(TODO): add issue #2	2025-05-01 17:49:34 +02:00
Rodney, Tiara	b159b44f7b	doc(TODO): init my poor-man's issue tracker, as I don't want to worry about the overhead of using a third-party service for this at the moment.	2025-05-01 17:49:34 +02:00
Rodney, Tiara	be34f5c670	chore: add override for jest jest has a deprecated dependency, this override fixes that	2025-05-01 17:47:01 +02:00
				`@ -0,0 +1 @@`
				`Subproject commit ee93479edce1da28f4abf68a362427f8d3134f80`