Add onIdChange function to Installations (#2486)

Author: mmermerkaya

packages/firebase/index.d.ts

@@ -1352,6 +1352,12 @@ declare namespace firebase.installations {
      * Deletes the Firebase Installation and all associated data.
      */
     delete(): Promise<void>;
+
+    /**
+     * Sets a new callback that will get called when Installlation ID changes.
+     * Returns an unsubscribe function that will remove the callback when called.
+     */
+    onIdChange(callback: (installationId: string) => void): () => void;
   }
 }
 

packages/installations-types/index.d.ts

@@ -37,6 +37,12 @@ export interface FirebaseInstallations {
    * Deletes the Firebase Installation and all associated data.
    */
   delete(): Promise<void>;
+
+  /**
+   * Sets a new callback that will get called when Installlation ID changes.
+   * Returns an unsubscribe function that will remove the callback when called.
+   */
+  onIdChange(callback: (installationId: string) => void): () => void;
 }
 
 export type FirebaseInstallationsName = 'installations';

packages/installations/src/functions/index.ts

@@ -15,6 +15,7 @@
  * limitations under the License.
  */
 
-export { getId } from './get-id';
-export { getToken } from './get-token';
-export { deleteInstallation } from './delete-installation';
+export * from './get-id';
+export * from './get-token';
+export * from './delete-installation';
+export * from './on-id-change';

packages/installations/src/functions/on-id-change.test.ts

@@ -0,0 +1,52 @@
+/**
+ * @license
+ * Copyright 2019 Google Inc.
+ *
+ * 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 { expect } from 'chai';
+import { stub } from 'sinon';
+import '../testing/setup';
+import { onIdChange } from './on-id-change';
+import * as FidChangedModule from '../helpers/fid-changed';
+import { getFakeDependencies } from '../testing/fake-generators';
+import { FirebaseDependencies } from '../interfaces/firebase-dependencies';
+
+describe('onIdChange', () => {
+  let dependencies: FirebaseDependencies;
+
+  beforeEach(() => {
+    dependencies = getFakeDependencies();
+    stub(FidChangedModule);
+  });
+
+  it('calls addCallback with the given callback and app key when called', () => {
+    const callback = stub();
+    onIdChange(dependencies, callback);
+    expect(FidChangedModule.addCallback).to.have.been.calledOnceWith(
+      dependencies.appConfig,
+      callback
+    );
+  });
+
+  it('calls removeCallback with the given callback and app key when unsubscribe is called', () => {
+    const callback = stub();
+    const unsubscribe = onIdChange(dependencies, callback);
+    unsubscribe();
+    expect(FidChangedModule.removeCallback).to.have.been.calledOnceWith(
+      dependencies.appConfig,
+      callback
+    );
+  });
+});

packages/installations/src/functions/on-id-change.ts

@@ -0,0 +1,37 @@
+/**
+ * @license
+ * Copyright 2019 Google Inc.
+ *
+ * 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 { addCallback, removeCallback } from '../helpers/fid-changed';
+import { FirebaseDependencies } from '../interfaces/firebase-dependencies';
+
+export type IdChangeCallbackFn = (installationId: string) => void;
+export type IdChangeUnsubscribeFn = () => void;
+
+/**
+ * Sets a new callback that will get called when Installation ID changes.
+ * Returns an unsubscribe function that will remove the callback when called.
+ */
+export function onIdChange(
+  { appConfig }: FirebaseDependencies,
+  callback: IdChangeCallbackFn
+): IdChangeUnsubscribeFn {
+  addCallback(appConfig, callback);
+
+  return () => {
+    removeCallback(appConfig, callback);
+  };
+}

packages/installations/src/helpers/fid-changed.test.ts

@@ -0,0 +1,103 @@
+/**
+ * @license
+ * Copyright 2019 Google Inc.
+ *
+ * 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 { expect } from 'chai';
+import { stub } from 'sinon';
+import '../testing/setup';
+import { AppConfig } from '../interfaces/app-config';
+import {
+  fidChanged,
+  addCallback,
+  removeCallback
+} from '../helpers/fid-changed';
+import { getFakeAppConfig } from '../testing/fake-generators';
+
+const FID = 'evil-lies-in-every-man';
+
+describe('onIdChange', () => {
+  describe('with single app', () => {
+    let appConfig: AppConfig;
+
+    beforeEach(() => {
+      appConfig = getFakeAppConfig();
+    });
+
+    it('calls the provided callback when FID changes', () => {
+      const stubFn = stub();
+      addCallback(appConfig, stubFn);
+
+      fidChanged(appConfig, FID);
+
+      expect(stubFn).to.have.been.calledOnceWith(FID);
+    });
+
+    it('calls multiple callbacks', () => {
+      const stubA = stub();
+      addCallback(appConfig, stubA);
+      const stubB = stub();
+      addCallback(appConfig, stubB);
+
+      fidChanged(appConfig, FID);
+
+      expect(stubA).to.have.been.calledOnceWith(FID);
+      expect(stubB).to.have.been.calledOnceWith(FID);
+    });
+
+    it('does not call removed callbacks', () => {
+      const stubFn = stub();
+      addCallback(appConfig, stubFn);
+
+      removeCallback(appConfig, stubFn);
+      fidChanged(appConfig, FID);
+
+      expect(stubFn).not.to.have.been.called;
+    });
+
+    it('does not throw when removeCallback is called multiple times', () => {
+      const stubFn = stub();
+      addCallback(appConfig, stubFn);
+
+      removeCallback(appConfig, stubFn);
+      removeCallback(appConfig, stubFn);
+      fidChanged(appConfig, FID);
+
+      expect(stubFn).not.to.have.been.called;
+    });
+  });
+
+  describe('with multiple apps', () => {
+    let appConfigA: AppConfig;
+    let appConfigB: AppConfig;
+
+    beforeEach(() => {
+      appConfigA = getFakeAppConfig();
+      appConfigB = getFakeAppConfig({ appName: 'differentAppName' });
+    });
+
+    it('calls the correct callback when FID changes', () => {
+      const stubA = stub();
+      addCallback(appConfigA, stubA);
+      const stubB = stub();
+      addCallback(appConfigB, stubB);
+
+      fidChanged(appConfigA, FID);
+
+      expect(stubA).to.have.been.calledOnceWith(FID);
+      expect(stubB).not.to.have.been.called;
+    });
+  });
+});

packages/installations/src/helpers/fid-changed.ts

@@ -0,0 +1,110 @@
+/**
+ * @license
+ * Copyright 2019 Google Inc.
+ *
+ * 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 { getKey } from '../util/get-key';
+import { AppConfig } from '../interfaces/app-config';
+import { IdChangeCallbackFn } from '../functions';
+
+const fidChangeCallbacks: Map<string, Set<IdChangeCallbackFn>> = new Map();
+
+/**
+ * Calls the onIdChange callbacks with the new FID value, and broadcasts the
+ * change to other tabs.
+ */
+export function fidChanged(appConfig: AppConfig, fid: string): void {
+  const key = getKey(appConfig);
+
+  callFidChangeCallbacks(key, fid);
+  broadcastFidChange(key, fid);
+}
+
+export function addCallback(
+  appConfig: AppConfig,
+  callback: IdChangeCallbackFn
+): void {
+  // Open the broadcast channel if it's not already open,
+  // to be able to listen to change events from other tabs.
+  getBroadcastChannel();
+
+  const key = getKey(appConfig);
+
+  let callbackSet = fidChangeCallbacks.get(key);
+  if (!callbackSet) {
+    callbackSet = new Set();
+    fidChangeCallbacks.set(key, callbackSet);
+  }
+  callbackSet.add(callback);
+}
+
+export function removeCallback(
+  appConfig: AppConfig,
+  callback: IdChangeCallbackFn
+): void {
+  const key = getKey(appConfig);
+
+  const callbackSet = fidChangeCallbacks.get(key);
+
+  if (!callbackSet) {
+    return;
+  }
+
+  callbackSet.delete(callback);
+  if (callbackSet.size === 0) {
+    fidChangeCallbacks.delete(key);
+  }
+
+  // Close broadcast channel if there are no more callbacks.
+  closeBroadcastChannel();
+}
+
+function callFidChangeCallbacks(key: string, fid: string): void {
+  const callbacks = fidChangeCallbacks.get(key);
+  if (!callbacks) {
+    return;
+  }
+
+  for (const callback of callbacks) {
+    callback(fid);
+  }
+}
+
+function broadcastFidChange(key: string, fid: string): void {
+  const channel = getBroadcastChannel();
+  if (channel) {
+    channel.postMessage({ key, fid });
+  }
+  closeBroadcastChannel();
+}
+
+let broadcastChannel: BroadcastChannel | null = null;
+/** Opens and returns a BroadcastChannel if it is supported by the browser. */
+function getBroadcastChannel(): BroadcastChannel | null {
+  if (!broadcastChannel && 'BroadcastChannel' in self) {
+    broadcastChannel = new BroadcastChannel('[Firebase] FID Change');
+    broadcastChannel.onmessage = e => {
+      callFidChangeCallbacks(e.data.key, e.data.fid);
+    };
+  }
+  return broadcastChannel;
+}
+
+function closeBroadcastChannel(): void {
+  if (fidChangeCallbacks.size === 0 && broadcastChannel) {
+    broadcastChannel.close();
+    broadcastChannel = null;
+  }
+}