Add internal delete method to functions (#1687)

Implement `INTERNAL.delete()` method for Functions service.

Author: hsubox76

packages/functions/src/api/service.ts

@@ -16,6 +16,7 @@
  */
 
 import { FirebaseApp } from '@firebase/app-types';
+import { FirebaseService } from '@firebase/app-types/private';
 import firebase from '@firebase/app';
 import {
   FirebaseFunctions,
@@ -53,10 +54,12 @@ function failAfter(millis: number): Promise<HttpResponse> {
 /**
  * The main class for the Firebase Functions SDK.
  */
-export class Service implements FirebaseFunctions {
+export class Service implements FirebaseFunctions, FirebaseService {
   private readonly contextProvider: ContextProvider;
   private readonly serializer = new Serializer();
   private emulatorOrigin: string | null = null;
+  private cancelAllRequests: Promise<void>;
+  private deleteService: Function;
 
   /**
    * Creates a new Functions service for the given app and (optional) region.
@@ -68,12 +71,24 @@ export class Service implements FirebaseFunctions {
     private region_: string = 'us-central1'
   ) {
     this.contextProvider = new ContextProvider(app_);
+    // Cancels all ongoing requests when resolved.
+    this.cancelAllRequests = new Promise(resolve => {
+      this.deleteService = () => {
+        return resolve();
+      };
+    });
   }
 
   get app(): FirebaseApp {
     return this.app_;
   }
 
+  INTERNAL = {
+    delete: (): Promise<void> => {
+      return this.deleteService();
+    }
+  };
+
   /**
    * Returns the URL for a callable with the given name.
    * @param name The name of the callable.
@@ -184,9 +199,18 @@ export class Service implements FirebaseFunctions {
 
     const response = await Promise.race([
       this.postJSON(url, body, headers),
-      failAfter(timeout)
+      failAfter(timeout),
+      this.cancelAllRequests
     ]);
 
+    // If service was deleted, interrupted response throws an error.
+    if (!response) {
+      throw new HttpsErrorImpl(
+        'cancelled',
+        'Firebase Functions instance was deleted.'
+      );
+    }
+
     // Check for an error status, regardless of http status.
     const error = _errorForResponse(
       response.status,