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.

src/manager.ts

@@ -71,20 +71,73 @@ 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);
+                this.loggers[scope] = rv;
+                this._fixupChildren(existing, rv);
+            }
+            else {
+                rv = existing;
+            }
         }
         else {
             rv = new (this._loggerClass ?? loggerClass)(scope, NOTSET);
             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;
             }
         }
     }