Firebase ML Node.js SDK Structure (#778)

* Firebase ML Node.js SDK Structure
* added tests

Author: ifielker

src/firebase-app.ts

@@ -22,13 +22,15 @@ import {FirebaseNamespaceInternals} from './firebase-namespace';
 import {AppErrorCodes, FirebaseAppError} from './utils/error';
 
 import {Auth} from './auth/auth';
+import {MachineLearning} from './machine-learning/machine-learning';
 import {Messaging} from './messaging/messaging';
 import {Storage} from './storage/storage';
 import {Database} from '@firebase/database';
 import {DatabaseService} from './database/database';
 import {Firestore} from '@google-cloud/firestore';
 import {FirestoreService} from './firestore/firestore';
 import {InstanceId} from './instance-id/instance-id';
+
 import {ProjectManagement} from './project-management/project-management';
 import {SecurityRules} from './security-rules/security-rules';
 
@@ -354,6 +356,19 @@ export class FirebaseApp {
     });
   }
 
+  /**
+   * Returns the MachineLearning service instance associated with this app.
+   *
+   * @return {MachineLearning} The Machine Learning service instance of this app
+   */
+  public machineLearning(): MachineLearning {
+    return this.ensureService_('machine-learning', () => {
+      const machineLearningService: typeof MachineLearning =
+          require('./machine-learning/machine-learning').MachineLearning;
+      return new machineLearningService(this);
+    });
+  }
+
   /**
    * Returns the ProjectManagement service instance associated with this app.
    *

src/firebase-namespace.ts

@@ -28,6 +28,7 @@ import {
 } from './auth/credential';
 
 import {Auth} from './auth/auth';
+import {MachineLearning} from './machine-learning/machine-learning';
 import {Messaging} from './messaging/messaging';
 import {Storage} from './storage/storage';
 import {Database} from '@firebase/database';
@@ -396,6 +397,21 @@ export class FirebaseNamespace {
     return fn;
   }
 
+  /**
+   * Gets the `MachineLearning` service namespace. The returned namespace can be
+   * used to get the `MachineLearning` service for the default app or an
+   * explicityly specified app.
+   */
+  get machineLearning(): FirebaseServiceNamespace<MachineLearning> {
+    const fn: FirebaseServiceNamespace<MachineLearning> =
+        (app?: FirebaseApp) => {
+          return this.ensureApp(app).machineLearning();
+        };
+    const machineLearning =
+        require('./machine-learning/machine-learning').MachineLearning;
+    return Object.assign(fn, {MachineLearning: machineLearning});
+  }
+
   /**
    * Gets the `InstanceId` service namespace. The returned namespace can be used to get the
    * `Instance` service for the default app or an explicitly specified app.