[js][storage] uploadTask.on now correctly handles next or observer args as per firebase web sdk

lib/modules/storage/reference.js

@@ -76,6 +76,14 @@ export default class StorageReference extends ReferenceBase {
     return new StorageTask(DOWNLOAD_TASK, FirebaseStorage.downloadFile(this.path, filePath), this);
   }
 
+  /**
+   * Alias to putFile
+   * @returns {StorageReference.putFile}
+   */
+  get put() {
+    return this.putFile;
+  }
+
   /**
    * Upload a file path
    * @param  {string} filePath The local path of the file

lib/modules/storage/task.js

@@ -1,22 +1,105 @@
+/* @flow */
+import { statics as StorageStatics } from './';
+import { isObject, isFunction } from './../../utils';
+import StorageReference from './reference';
+
 export const UPLOAD_TASK = 'upload';
 export const DOWNLOAD_TASK = 'download';
 
+declare type UploadTaskSnapshotType = {
+  bytesTransferred: number,
+  downloadURL: string|null,
+  metadata: Object, // TODO flow type def for https://firebase.google.com/docs/reference/js/firebase.storage.FullMetadata.html
+  ref: StorageReference,
+  state: StorageStatics.TaskState.RUNNING
+    |StorageStatics.TaskState.PAUSED
+    |StorageStatics.TaskState.SUCCESS
+    |StorageStatics.TaskState.CANCELLED
+    |StorageStatics.TaskState.ERROR,
+  task: StorageTask,
+  totalBytes: number,
+};
+
+declare type FuncSnapshotType = null|(snapshot: UploadTaskSnapshotType) => any;
+
+declare type FuncErrorType = null|(error: Error) => any;
+
+declare type NextOrObserverType = null
+  |{ next?: FuncSnapshotType, error?: FuncErrorType, complete?:FuncSnapshotType }
+  |FuncSnapshotType;
+
 /**
  * @url https://firebase.google.com/docs/reference/js/firebase.storage.UploadTask
  */
 export default class StorageTask {
-  constructor(type: string, promise, storageRef) {
+  constructor(type: UPLOAD_TASK|DOWNLOAD_TASK, promise: Promise, storageRef: StorageReference) {
     this.type = type;
     this.ref = storageRef;
-    this.promise = promise;
     this.storage = storageRef.storage;
     this.path = storageRef.path;
 
     // 'proxy' original promise
-    this.then = promise.then.bind(promise);
+    this.then = promise.then(this._interceptSnapshotEvent);
     this.catch = promise.catch.bind(promise);
   }
 
+  /**
+   * Intercepts a native snapshot result object attaches ref / task instances
+   * and calls the original function
+   * @returns {Promise.<T>}
+   * @private
+   */
+  _interceptSnapshotEvent(f: Function|null|undefined): null|() => any {
+    if (!isFunction(f)) return null;
+    return (snapshot) => {
+      const _snapshot = Object.assign({}, snapshot);
+      _snapshot.task = this;
+      _snapshot.ref = this.ref;
+      return f(_snapshot);
+    };
+  }
+
+  /**
+   * Intercepts a error object form native and converts to a JS Error
+   * @param f
+   * @returns {*}
+   * @private
+   */
+  _interceptErrorEvent(f: Function|null|undefined): null|() => any {
+    if (!isFunction(f)) return null;
+    return (error) => {
+      const _error = new Error(error.message);
+      _error.code = error.code;
+      return f(_error);
+    };
+  }
+
+  /**
+   *
+   * @param nextOrObserver
+   * @param error
+   * @param complete
+   * @returns {function()}
+   * @private
+   */
+  _subscribe(nextOrObserver: NextOrObserverType, error: FuncErrorType, complete: FuncSnapshotType): Function {
+    const observer = isObject(nextOrObserver);
+
+    const _error = this._interceptErrorEvent(observer ? nextOrObserver.error : error);
+    const _next = this._interceptSnapshotEvent(observer ? nextOrObserver.next : nextOrObserver);
+    const _complete = this._interceptSnapshotEvent(observer ? nextOrObserver.complete : complete);
+
+    if (_next) this.storage._addListener(this.path, StorageStatics.TaskEvent.STATE_CHANGED, _next);
+    if (_error) this.storage._addListener(this.path, `${this.type}_failure`, _error);
+    if (_complete) this.storage._addListener(this.path, `${this.type}_success`, _complete);
+
+    return () => {
+      if (_next) this.storage._removeListener(this.path, StorageStatics.TaskEvent.STATE_CHANGED, _next);
+      if (_error) this.storage._removeListener(this.path, `${this.type}_failure`, _error);
+      if (_complete) this.storage._removeListener(this.path, `${this.type}_success`, _complete);
+    };
+  }
+
   /**
    *
    * @param event
@@ -25,21 +108,24 @@ export default class StorageTask {
    * @param complete
    * @returns {function()}
    */
-  on(event = 'state_changed', nextOrObserver, error, complete) {
-    if (nextOrObserver) this.storage._addListener(this.path, 'state_changed', nextOrObserver);
-    if (error) this.storage._addListener(this.path, `${this.type}_failure`, error);
-    if (complete) this.storage._addListener(this.path, `${this.type}_success`, complete);
-    // off
-    // todo support add callback syntax as per https://firebase.google.com/docs/reference/js/firebase.storage.UploadTask#on
-    return () => {
-      if (nextOrObserver) this.storage._removeListener(this.path, 'state_changed', nextOrObserver);
-      if (error) this.storage._removeListener(this.path, `${this.type}_failure`, error);
-      if (complete) this.storage._removeListener(this.path, `${this.type}_success`, complete);
-    };
+  on(event: string = StorageStatics.TaskEvent.STATE_CHANGED, nextOrObserver: NextOrObserverType, error: FuncErrorType, complete: FuncSnapshotType): Function {
+    if (!event) {
+      throw new Error('StorageTask.on listener is missing required string argument \'event\'.');
+    }
+
+    if (event !== StorageStatics.TaskEvent.STATE_CHANGED) {
+      throw new Error(`StorageTask.on event argument must be a string with a value of '${StorageStatics.TaskEvent.STATE_CHANGED}'`);
+    }
+
+    // if only event provided return the subscriber function
+    if (!nextOrObserver && !error && !complete) {
+      return this._subscribe.bind(this);
+    }
+
+    return this._subscribe(event, nextOrObserver, error, complete);
   }
 
   pause() {
-    // todo
     throw new Error('.pause() is not currently supported by react-native-firebase');
   }