Implement lightweight FirebaseApp (#109)

* Implement lightweight firebase app

Add firebaseApp Lite

add tests for firebaseApp Lite

add firebaseApp lite entry point

[AUTOMATED]: Prettier Code Styling

[AUTOMATED]: License Headers

* share code between regular firebaseNamespace and the lite version

* [AUTOMATED]: Prettier Code Styling

* [AUTOMATED]: License Headers

* check self for existing firebase instance

* [AUTOMATED]: Prettier Code Styling

* remove unused code

* update to use a shorter message

* [AUTOMATED]: Prettier Code Styling

* update warning message

* [AUTOMATED]: Prettier Code Styling

* update warning message

* resolve mertcan's comments

* [AUTOMATED]: Prettier Code Styling

* use readonly

* use _ as suffix

* address code style issues

* add a build target for app lite

* [AUTOMATED]: Prettier Code Styling

* add readonly attribute

* use const

* use String to coerce to string type

* remove unnecessary assertion

* misc style fixes

* [AUTOMATED]: Prettier Code Styling

* rename variables

* add type to parameters

* reformat comments

* use object instead Object

* use uppercase for const

Author: Feiyang1

packages/app/index.lite.ts

@@ -0,0 +1,22 @@
+/**
+ * @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 { createFirebaseNamespaceLite } from './src/lite/firebaseNamespaceLite';
+
+export const firebase = createFirebaseNamespaceLite();
+
+export default firebase;

packages/app/index.ts

@@ -40,6 +40,22 @@ to false and "main" to true:
 https://github.com/rollup/rollup-plugin-node-resolve
 `);
 
+// Firebase Lite detection
+if (self && 'firebase' in self) {
+  console.warn(`
+    Warning: Firebase is already defined in the global scope. Please make sure
+    Firebase library is only loaded once.
+  `);
+
+  const sdkVersion = ((self as any).firebase as FirebaseNamespace).SDK_VERSION;
+  if (sdkVersion.includes('LITE')) {
+    console.warn(`
+    Warning: You are trying to load Firebase while using Firebase Performance standalone script.
+    You should load Firebase Performance with this instance of Firebase to avoid loading duplicate code.
+    `);
+  }
+}
+
 export const firebase = createFirebaseNamespace();
 
 export default firebase;

packages/app/rollup.config.js

@@ -69,5 +69,15 @@ export default [
       [...deps, 'react-native'].some(
         dep => id === dep || id.startsWith(`${dep}/`)
       )
+  },
+  {
+    input: 'index.lite.ts',
+    output: {
+      file: 'dist/index.lite.js',
+      format: 'esm',
+      sourcemap: true
+    },
+    plugins,
+    external: id => deps.some(dep => id === dep || id.startsWith(`${dep}/`))
   }
 ];

packages/app/src/constants.ts

@@ -0,0 +1,18 @@
+/**
+ * @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.
+ */
+
+export const DEFAULT_ENTRY_NAME = '[DEFAULT]';

packages/app/src/errors.ts

@@ -26,7 +26,7 @@ export const enum AppError {
   INVALID_APP_ARGUMENT = 'invalid-app-argument'
 }
 
-const errors: ErrorMap<AppError> = {
+const ERRORS: ErrorMap<AppError> = {
   [AppError.NO_APP]:
     "No Firebase App '{$name}' has been created - " +
     'call Firebase App.initializeApp()',
@@ -40,7 +40,7 @@ const errors: ErrorMap<AppError> = {
     'Firebase App instance.'
 };
 
-const appErrors = new ErrorFactory('app', 'Firebase', errors);
+const appErrors = new ErrorFactory<AppError>('app', 'Firebase', ERRORS);
 
 export function error(code: AppError, args?: { [name: string]: any }) {
   throw appErrors.create(code, args);

packages/app/src/firebaseApp.ts

@@ -18,18 +18,23 @@
 import {
   FirebaseApp,
   FirebaseOptions,
-  FirebaseNamespace,
   FirebaseAppConfig
 } from '@firebase/app-types';
 import {
   _FirebaseApp,
   _FirebaseNamespace,
-  FirebaseService
+  FirebaseService,
+  FirebaseAppInternals
 } from '@firebase/app-types/private';
 import { deepCopy, deepExtend } from '@firebase/util';
 import { error, AppError } from './errors';
+import { DEFAULT_ENTRY_NAME } from './constants';
 
-export const DEFAULT_ENTRY_NAME = '[DEFAULT]';
+interface ServicesCache {
+  [name: string]: {
+    [serviceName: string]: FirebaseService;
+  };
+}
 
 // An array to capture listeners before the true auth functions
 // exist
@@ -40,25 +45,21 @@ let tokenListeners: any[] = [];
  * a shared authentication state.
  */
 export class FirebaseAppImpl implements FirebaseApp {
-  private options_: FirebaseOptions;
-  private name_: string;
+  private readonly options_: FirebaseOptions;
+  private readonly name_: string;
   private isDeleted_ = false;
-  private services_: {
-    [name: string]: {
-      [serviceName: string]: FirebaseService;
-    };
-  } = {};
-  private _automaticDataCollectionEnabled: boolean;
+  private services_: ServicesCache = {};
+  private automaticDataCollectionEnabled_: boolean;
 
-  public INTERNAL;
+  INTERNAL: FirebaseAppInternals;
 
   constructor(
     options: FirebaseOptions,
     config: FirebaseAppConfig,
-    private firebase_: FirebaseNamespace
+    private readonly firebase_: _FirebaseNamespace
   ) {
     this.name_ = config.name!;
-    this._automaticDataCollectionEnabled =
+    this.automaticDataCollectionEnabled_ =
       config.automaticDataCollectionEnabled || false;
     this.options_ = deepCopy<FirebaseOptions>(options);
     this.INTERNAL = {
@@ -79,12 +80,12 @@ export class FirebaseAppImpl implements FirebaseApp {
 
   get automaticDataCollectionEnabled(): boolean {
     this.checkDestroyed_();
-    return this._automaticDataCollectionEnabled;
+    return this.automaticDataCollectionEnabled_;
   }
 
   set automaticDataCollectionEnabled(val) {
     this.checkDestroyed_();
-    this._automaticDataCollectionEnabled = val;
+    this.automaticDataCollectionEnabled_ = val;
   }
 
   get name(): string {
@@ -103,16 +104,18 @@ export class FirebaseAppImpl implements FirebaseApp {
       resolve();
     })
       .then(() => {
-        (this.firebase_ as _FirebaseNamespace).INTERNAL.removeApp(this.name_);
-        let services: FirebaseService[] = [];
-        Object.keys(this.services_).forEach(serviceKey => {
-          Object.keys(this.services_[serviceKey]).forEach(instanceKey => {
+        this.firebase_.INTERNAL.removeApp(this.name_);
+        const services: FirebaseService[] = [];
+
+        for (const serviceKey of Object.keys(this.services_)) {
+          for (const instanceKey of Object.keys(this.services_[serviceKey])) {
             services.push(this.services_[serviceKey][instanceKey]);
-          });
-        });
+          }
+        }
+
         return Promise.all(
           services.map(service => {
-            return service.INTERNAL!.delete();
+            return service.INTERNAL.delete();
           })
         );
       })
@@ -157,9 +160,11 @@ export class FirebaseAppImpl implements FirebaseApp {
         instanceIdentifier !== DEFAULT_ENTRY_NAME
           ? instanceIdentifier
           : undefined;
-      const service = (this.firebase_ as _FirebaseNamespace).INTERNAL.factories[
-        name
-      ](this, this.extendApp.bind(this), instanceSpecifier);
+      const service = this.firebase_.INTERNAL.factories[name](
+        this,
+        this.extendApp.bind(this),
+        instanceSpecifier
+      );
       this.services_[name][instanceIdentifier] = service;
     }