Fixing GCS typings (#340)

Author: hiranya911

package-lock.json

@@ -61,7 +61,7 @@
   "optionalDependencies": {
     "@google-cloud/firestore": "^0.16.0",
     "@google-cloud/storage": "^1.6.0",
-    "@types/google-cloud__storage": "^1.1.7"
+    "@types/google-cloud__storage": "^1.7.1"
   },
   "devDependencies": {
     "@types/chai": "^3.4.34",

package.json

@@ -41,10 +41,10 @@ class StorageInternals implements FirebaseServiceInternalsInterface {
  * Storage service bound to the provided app.
  */
 export class Storage implements FirebaseServiceInterface {
-  public INTERNAL: StorageInternals = new StorageInternals();
+  public readonly INTERNAL: StorageInternals = new StorageInternals();
 
-  private appInternal: FirebaseApp;
-  private storageClient: any;
+  private readonly appInternal: FirebaseApp;
+  private readonly storageClient: gcs;
 
   /**
    * @param {FirebaseApp} app The app for this Storage service.
@@ -74,7 +74,7 @@ export class Storage implements FirebaseServiceInterface {
     if (cert != null) {
       // cert is available when the SDK has been initialized with a service account JSON file,
       // or by setting the GOOGLE_APPLICATION_CREDENTIALS envrionment variable.
-      this.storageClient = storage({
+      this.storageClient = new storage({
         projectId: cert.projectId,
         credentials: {
           private_key: cert.privateKey,
@@ -83,7 +83,7 @@ export class Storage implements FirebaseServiceInterface {
       });
     } else if (app.options.credential instanceof ApplicationDefaultCredential) {
       // Try to use the Google application default credentials.
-      this.storageClient = storage();
+      this.storageClient = new storage();
     } else {
       throw new FirebaseError({
         code: 'storage/invalid-credential',