moves config into its own file

src/observable/index.ts

@@ -18,40 +18,15 @@ import {SortedMapList} from "./list/SortedMapList.js";
 import {FilteredMap} from "./map/FilteredMap.js";
 import {MappedMap} from "./map/MappedMap.js";
 import {JoinedMap} from "./map/JoinedMap.js";
-import {BaseObservableMap, BaseObservableMapConfig} from "./map/BaseObservableMap";
-import {ObservableMapInternal} from "./map/ObservableMap";
-// re-export "root" (of chain) collections
+import {BaseObservableMap} from "./map/BaseObservableMap";
+// re-export "root" (of chain) collection
+export { ObservableMap } from "./map/ObservableMap";
 export { ObservableArray } from "./list/ObservableArray";
 export { SortedArray } from "./list/SortedArray";
 export { MappedList } from "./list/MappedList";
 export { AsyncMappedList } from "./list/AsyncMappedList";
 export { ConcatList } from "./list/ConcatList";
 
-// avoid circular dependency between these classes
-// and BaseObservableMap (as they extend it)
-function config<K, V>(): BaseObservableMapConfig<K, V> {
-    return {
-        join: (_this: BaseObservableMap<K, V>, ...otherMaps: Array<BaseObservableMap<K, V>>): JoinedMap => {
-            return new JoinedMap([_this].concat(otherMaps));
-        },
-        mapValues: (_this: BaseObservableMap<K, V>, mapper: any, updater?: (params: any) => void): MappedMap => {
-            return new MappedMap(_this, mapper, updater);
-        },
-        sortValues: (_this: BaseObservableMap<K, V>, comparator?: (a: any, b: any) => number): SortedMapList => {
-            return new SortedMapList(_this, comparator);
-        },
-        filterValues: (_this: BaseObservableMap<K, V>, filter: (v: V, k: K) => boolean): FilteredMap => {
-            return new FilteredMap(_this, filter);
-        }
-    };
-};
-
-
-export class ObservableMap<K, V> extends ObservableMapInternal<K, V> {
-    constructor(initialValues?: (readonly [K, V])[]) {
-        super(config<K, V>(), initialValues);
-    }
-}
 
 // avoid circular dependency between these classes
 // and BaseObservableMap (as they extend it)

src/observable/map/BaseObservableMap.ts

@@ -60,10 +60,17 @@ export abstract class BaseObservableMap<K, V> extends BaseObservable<IMapObserve
         }
     }
 
+    // The following group of functions have a default implementation
+    // in the neighboring `config.ts`. See the comment in that file for
+    // the explanation for why the default implementation isn't defined
+    // here. See the neighboring `ObservableMap.ts` for an example of how
+    // to easily use the default implementation in a class that extends
+    // this one (which is most likely what you want to do).
     abstract join(...otherMaps: Array<typeof this>): JoinedMap;
     abstract mapValues(mapper: any, updater?: (params: any) => void): MappedMap;
     abstract sortValues(comparator?: (a: any, b: any) => number): SortedMapList;
     abstract filterValues(filter: (v: V, k: K) => boolean): FilteredMap;
+
     abstract [Symbol.iterator](): Iterator<[K, V]>;
     abstract get size(): number;
     abstract get(key: K): V | undefined;

src/observable/map/ObservableMap.ts

@@ -15,18 +15,20 @@ limitations under the License.
 */
 
 import {BaseObservableMap, BaseObservableMapConfig} from "./BaseObservableMap";
-import {JoinedMap} from "../map/JoinedMap.js";
-import {MappedMap} from "../map/MappedMap.js";
-import {FilteredMap} from "../map/FilteredMap.js";
+import {config} from "./config";
+import {JoinedMap} from "./JoinedMap.js";
+import {MappedMap} from "./MappedMap.js";
+import {FilteredMap} from "./FilteredMap.js";
 import {SortedMapList} from "../list/SortedMapList.js";
 
-export class ObservableMapInternal<K, V> extends BaseObservableMap<K, V> {
+
+export class ObservableMap<K, V> extends BaseObservableMap<K, V> {
     private _config: BaseObservableMapConfig<K, V>
     private readonly _values: Map<K, V>;
 
-    constructor(config: BaseObservableMapConfig<K, V>, initialValues?: (readonly [K, V])[]) {
+    constructor(initialValues?: (readonly [K, V])[]) {
         super();
-        this._config = config;
+        this._config = config<K, V>();
         this._values = new Map(initialValues);
     }
 

src/observable/map/config.ts

@@ -0,0 +1,43 @@
+/*
+Copyright 2022 Isaiah Becker-Mayer <ibeckermayer@gmail.com>
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+import {BaseObservableMap, BaseObservableMapConfig} from "./BaseObservableMap";
+import {FilteredMap} from "./FilteredMap.js";
+import {MappedMap} from "./MappedMap.js";
+import {JoinedMap} from "./JoinedMap.js";
+import {SortedMapList} from "../list/SortedMapList.js";
+
+
+// This function is used as a default implementation of
+// the respective abstract functions in BaseObservableMap.
+// We implement it this way in order to avoid a circular
+// dependency between the classes that are instantiated here
+// (i.e. `new JoinedMap()`) and BaseObservableMap (as they extend it).
+export function config<K, V>(): BaseObservableMapConfig<K, V> {
+    return {
+        join: (_this: BaseObservableMap<K, V>, ...otherMaps: Array<BaseObservableMap<K, V>>): JoinedMap => {
+            return new JoinedMap([_this].concat(otherMaps));
+        },
+        mapValues: (_this: BaseObservableMap<K, V>, mapper: any, updater?: (params: any) => void): MappedMap => {
+            return new MappedMap(_this, mapper, updater);
+        },
+        sortValues: (_this: BaseObservableMap<K, V>, comparator?: (a: any, b: any) => number): SortedMapList => {
+            return new SortedMapList(_this, comparator);
+        },
+        filterValues: (_this: BaseObservableMap<K, V>, filter: (v: V, k: K) => boolean): FilteredMap => {
+            return new FilteredMap(_this, filter);
+        }
+    };
+};