feat(rxjs-core): add mixInSubscriptionManager()

projects/integration/src/app/api-tests/rxjs-core.spec.ts

@@ -11,6 +11,7 @@ import {
   mapAndCacheArrayElements,
   mapAndCacheObjectElements,
   mapToLatestFrom,
+  mixInSubscriptionManager,
   skipAfter,
   SubscriptionManager,
   withHistory,
@@ -60,6 +61,10 @@ describe('rxjs-core', () => {
       expect(mapToLatestFrom).toBeDefined();
     });
 
+    it('has mixInSubscriptionManager', () => {
+      expect(mixInSubscriptionManager).toBeDefined();
+    });
+
     it('has skipAfter', () => {
       expect(skipAfter).toBeDefined();
     });

projects/ng-core/src/typing-tests/tsconfig.json

@@ -12,6 +12,7 @@
     "baseUrl": "../lib",
     "experimentalDecorators": true,
     "paths": {
+      "@s-libs/js-core": ["../../../../dist/js-core"],
       "@s-libs/micro-dash": ["../../../../dist/micro-dash"],
       "@s-libs/rxjs-core": ["../../../../dist/rxjs-core"]
     }

projects/rxjs-core/src/lib/index.ts

@@ -1,4 +1,7 @@
 export * from './operators';
 export { createOperatorFunction } from './create-operator-function';
 export { logToReduxDevtoolsExtension } from './devtools/log-to-redux-devtools-extension';
-export { SubscriptionManager } from './subscription-manager';
+export {
+  mixInSubscriptionManager,
+  SubscriptionManager,
+} from './subscription-manager';

projects/rxjs-core/src/lib/subscription-manager.spec.ts

@@ -1,5 +1,9 @@
+import { expectSingleCallAndReset } from '@s-libs/ng-dev';
 import { of, Subject, throwError } from 'rxjs';
-import { SubscriptionManager } from './subscription-manager';
+import {
+  mixInSubscriptionManager,
+  SubscriptionManager,
+} from './subscription-manager';
 
 describe('SubscriptionManager', () => {
   let next: jasmine.Spy;
@@ -132,3 +136,25 @@ describe('SubscriptionManager', () => {
     });
   });
 });
+
+describe('mixInSubscriptionManager()', () => {
+  it('add SubscriptionManager abilities to a subclass', () => {
+    class DateManager extends mixInSubscriptionManager(Date) {}
+    const spy = jasmine.createSpy();
+    const subject = new Subject();
+    const dateManager = new DateManager();
+
+    dateManager.subscribeTo(subject, spy);
+    subject.next('value');
+
+    expectSingleCallAndReset(spy, 'value');
+  });
+
+  it('retains the abilities of the other superclass', () => {
+    class DateManager extends mixInSubscriptionManager(Date) {}
+
+    const dateManager = new DateManager('2020-11-27');
+
+    expect(dateManager.getFullYear()).toBe(2020);
+  });
+});

projects/rxjs-core/src/lib/subscription-manager.ts

@@ -1,5 +1,44 @@
+import { Constructor } from '@s-libs/js-core';
 import { Observable, Subscription, Unsubscribable } from 'rxjs';
 
+/**
+ * Mixes in {@link SubscriptionManager} as an additional superclass.
+ *
+ * ```ts
+ * class MySubclass extends mixInSubscriptionManager(MyOtherSuperclass) {
+ *   subscribeAndManage(observable: Observable<any>) {
+ *     this.subscribeTo(observable);
+ *   }
+ * }
+ * ```
+ */
+// tslint:disable-next-line:typedef
+export function mixInSubscriptionManager<B extends Constructor>(Base: B) {
+  return class extends Base implements Unsubscribable {
+    #subscriptions = new Subscription();
+
+    subscribeTo<T>(
+      observable: Observable<T>,
+      next?: (value: T) => void,
+      error?: (error: any) => void,
+      complete?: () => void,
+    ): void {
+      this.#subscriptions.add(
+        observable.subscribe(
+          next?.bind(this),
+          error?.bind(this),
+          complete?.bind(this),
+        ),
+      );
+    }
+
+    unsubscribe(): void {
+      this.#subscriptions.unsubscribe();
+      this.#subscriptions = new Subscription();
+    }
+  };
+}
+
 /**
  * Tracks all subscriptions to easily unsubscribe from them all during cleanup. Also binds callbacks to `this` for convenient use as a superclass, e.g.:
  *
@@ -19,30 +58,4 @@ import { Observable, Subscription, Unsubscribable } from 'rxjs';
  * }
  * ```
  */
-export class SubscriptionManager implements Unsubscribable {
-  private subscriptions = new Subscription();
-
-  subscribeTo<T>(
-    observable: Observable<T>,
-    next?: (value: T) => void,
-    error?: (error: any) => void,
-    complete?: () => void,
-  ): void {
-    this.subscriptions.add(
-      observable.subscribe(
-        this.bind(next),
-        this.bind(error),
-        this.bind(complete),
-      ),
-    );
-  }
-
-  unsubscribe(): void {
-    this.subscriptions.unsubscribe();
-    this.subscriptions = new Subscription();
-  }
-
-  private bind<T extends (val?: any) => void>(fn?: T): T | undefined {
-    return fn?.bind(this);
-  }
-}
+export class SubscriptionManager extends mixInSubscriptionManager(Object) {}