diff --git a/android/src/main/java/io/fullstack/firestack/FirestackStorage.java b/android/src/main/java/io/fullstack/firestack/FirestackStorage.java
index 21ed217..882e312 100644
--- a/android/src/main/java/io/fullstack/firestack/FirestackStorage.java
+++ b/android/src/main/java/io/fullstack/firestack/FirestackStorage.java
@@ -113,16 +113,10 @@ public void downloadFile(final String urlStr,
       @Override
       public void doInBackground(StreamDownloadTask.TaskSnapshot taskSnapshot, InputStream inputStream) throws IOException {
         int indexOfLastSlash = localFile.lastIndexOf("/");
-        String pathMinusFileName = localFile.substring(0, indexOfLastSlash) + "/";
-        String filename = localFile.substring(indexOfLastSlash+1);
+        String pathMinusFileName = indexOfLastSlash>0 ? localFile.substring(0, indexOfLastSlash) + "/" : "/";
+        String filename = indexOfLastSlash>0 ? localFile.substring(indexOfLastSlash+1) : localFile;
         File fileWithJustPath = new File(pathMinusFileName);
-        if (!fileWithJustPath.mkdirs()) {
-          Log.e(TAG, "Directory not created");
-          WritableMap error = Arguments.createMap();
-          error.putString("message", "Directory not created");
-          callback.invoke(error);
-          return;
-        }
+        fileWithJustPath.mkdirs();
         File fileWithFullPath = new File(pathMinusFileName, filename);
         FileOutputStream output = new FileOutputStream(fileWithFullPath);
         int bufferSize = 1024;
diff --git a/android/src/main/java/io/fullstack/firestack/FirestackUtils.java b/android/src/main/java/io/fullstack/firestack/FirestackUtils.java
index 669e337..1625e6c 100644
--- a/android/src/main/java/io/fullstack/firestack/FirestackUtils.java
+++ b/android/src/main/java/io/fullstack/firestack/FirestackUtils.java
@@ -40,7 +40,7 @@ public static void todoNote(final String tag, final String name, final Callback
   public static void sendEvent(final ReactContext context,
                                final String eventName,
                                final WritableMap params) {
-    if (context.hasActiveCatalystInstance()) {
+    if (context != null && context.hasActiveCatalystInstance()) {
       context
           .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
           .emit(eventName, params);
diff --git a/firestack.android.js b/firestack.android.js
index 15d7185..3ebc35e 100644
--- a/firestack.android.js
+++ b/firestack.android.js
@@ -1,7 +1,6 @@
 /**
- * @providesModule Firestack
  * @flow
  */
 import Firestack from './lib/firestack'
 
-export default Firestack
\ No newline at end of file
+export default Firestack
diff --git a/firestack.ios.js b/firestack.ios.js
index bc1e69b..3ebc35e 100644
--- a/firestack.ios.js
+++ b/firestack.ios.js
@@ -1,5 +1,4 @@
 /**
- * @providesModule Firestack
  * @flow
  */
 import Firestack from './lib/firestack'
diff --git a/lib/firestack.js b/lib/firestack.js
index 1bf9153..2961ed0 100644
--- a/lib/firestack.js
+++ b/lib/firestack.js
@@ -34,7 +34,7 @@ export default class Firestack extends Singleton {
    * @param options
    * @param name - TODO support naming multiple instances
    */
-  constructor(options: Object, name: string) {
+  constructor(options: Object, name?: string) {
     const instance = super(options);
 
     instance.options = options || {};
@@ -192,7 +192,7 @@ export default class Firestack extends Singleton {
   /**
    * Redux store
    **/
-  get store(): Object {
+  get store(): ?Object {
     return this._store;
   }
 
diff --git a/lib/modules/auth.js b/lib/modules/auth.js
index 04e5775..e871c97 100644
--- a/lib/modules/auth.js
+++ b/lib/modules/auth.js
@@ -138,7 +138,7 @@ export default class Auth extends Base {
    * Sign the user in with a third-party authentication provider
    * @return {Promise}           A promise resolved upon completion
    */
-  signInWithCredential(credential): Promise<Object> {
+  signInWithCredential(credential: Object): Promise<Object> {
     return promisify('signInWithProvider', FirestackAuth)(credential.provider, credential.token, credential.secret);
   }
 
@@ -146,7 +146,7 @@ export default class Auth extends Base {
    * Re-authenticate a user with a third-party authentication provider
    * @return {Promise}         A promise resolved upon completion
    */
-  reauthenticateUser(credential): Promise<Object> {
+  reauthenticateUser(credential: Object): Promise<Object> {
     return promisify('reauthenticateWithCredentialForProvider', FirestackAuth)(credential.provider, credential.token, credential.secret);
   }
 
diff --git a/lib/modules/base.js b/lib/modules/base.js
index 7aee499..443eafa 100644
--- a/lib/modules/base.js
+++ b/lib/modules/base.js
@@ -11,8 +11,9 @@ const FirestackModuleEvt = new NativeEventEmitter(FirestackModule);
 
 const logs = {};
 
+type FirestackOptions = {};
 export class Base extends EventEmitter {
-  constructor(firestack, options = {}) {
+  constructor(firestack: Object, options: FirestackOptions = {}) {
     super();
     this.firestack = firestack;
     this.eventHandlers = {};
@@ -22,7 +23,7 @@ export class Base extends EventEmitter {
   }
 
   // Logger
-  get log() {
+  get log(): Log {
     if (!logs[this.namespace]) {
       const debug = this.firestack._debug;
       logs[this.namespace] = new Log(this.namespace, debug);
@@ -38,7 +39,7 @@ export class Base extends EventEmitter {
   }
 
   // TODO unused - do we need this anymore?
-  _addToFirestackInstance(...methods) {
+  _addToFirestackInstance(...methods: Array<string>) {
     methods.forEach(name => {
       this.firestack[name] = this[name].bind(this);
     })
@@ -47,15 +48,17 @@ export class Base extends EventEmitter {
   /**
    * app instance
    **/
-  get app() {
+  get app(): Object {
     return this.firestack.app;
   }
 
-  whenReady(fn) {
-    return this.firestack.configurePromise.then(fn);
+  whenReady(promise: Promise<*>): Promise<*> {
+    return this.firestack.configurePromise.then((result) => {
+      return promise;
+    });
   }
 
-  get namespace() {
+  get namespace(): string {
     return 'firestack:base';
   }
 
@@ -88,25 +91,21 @@ export class Base extends EventEmitter {
 }
 
 export class ReferenceBase extends Base {
-  constructor(firestack, path) {
+  constructor(firestack: Object, path: Array<string> | string) {
     super(firestack);
 
-    this.path = Array.isArray(path) ?
-      path :
-      (typeof path == 'string' ?
-        [path] : []);
+    this.path = Array.isArray(path) ?  path : (typeof path == 'string' ?  [path] : []);
 
     // sanitize path, just in case
-    this.path = this.path
-      .filter(str => str !== "");
+    this.path = this.path.filter(str => str !== '');
   }
 
-  get key() {
+  get key(): string {
     const path = this.path;
     return path.length === 0 ? '/' : path[path.length - 1];
   }
 
-  pathToString() {
+  pathToString(): string {
     let path = this.path;
     let pathStr = (path.length > 0 ? path.join('/') : '/');
     if (pathStr[0] != '/') {
diff --git a/lib/modules/storage.js b/lib/modules/storage.js
index c5fc6c2..e734703 100644
--- a/lib/modules/storage.js
+++ b/lib/modules/storage.js
@@ -1,3 +1,4 @@
+/* @flow */
 
 import {NativeModules, NativeEventEmitter} from 'react-native';
 const FirestackStorage = NativeModules.FirestackStorage;
@@ -13,9 +14,14 @@ class StorageRef extends ReferenceBase {
     this.storage = storage;
   }
 
-  downloadUrl() {
+  downloadUrl(): Promise<Object> {
     const path = this.pathToString();
-    return promisify('downloadUrl', FirestackStorage)(this.storage.storageUrl, path);
+    this.log.debug('downloadUrl(', path, ')');
+    return promisify('downloadUrl', FirestackStorage)(this.storage.storageUrl, path)
+      .catch(err => {
+        this.log.error('Error downloading URL for ', path, '.  Error: ', err);
+        throw err;
+      });
   }
 
   /**
@@ -23,7 +29,7 @@ class StorageRef extends ReferenceBase {
    * @param {String} downloadPath Where to store the file
    * @return {Promise}
    */
-  download (downloadPath, cb) {
+  download (downloadPath: string, cb: (evt: Object) => Object): Promise<Object> {
     let callback = cb;
     if (!callback || typeof callback !== 'function') {
       callback = (evt) => {};
@@ -35,20 +41,25 @@ class StorageRef extends ReferenceBase {
     listeners.push(this.storage._addListener('download_resumed', callback));
 
     const path = this.pathToString();
+    this.log.debug('download(', path, ') -> ', downloadPath);
     return promisify('downloadFile', FirestackStorage)(this.storage.storageUrl, path, downloadPath)
       .then((res) => {
-        console.log('res --->', res);
-        listeners.forEach(this.storage._removeListener);
+        this.log.debug('res --->', res);
+        listeners.forEach(listener => listener.remove());
         return res;
       })
       .catch(err => {
-        console.log('Got an error ->', err);
-      })
+        this.log.error('Error downloading ', path, ' to ', downloadPath, '.  Error: ', err);
+        throw err;
+      });
   }
 }
 
+type StorageOptionsType = {
+  storageBucket?: ?string,
+};
 export default class Storage extends Base {
-  constructor(firestack, options={}) {
+  constructor(firestack: Object, options:StorageOptionsType={}) {
     super(firestack, options);
 
     if (this.options.storageBucket) {
@@ -58,8 +69,8 @@ export default class Storage extends Base {
     this.refs = {};
   }
 
-  ref(...path) {
-    const key = this._pathKey(path);
+  ref(...path: Array<string>): StorageRef {
+    const key = this._pathKey(...path);
     if (!this.refs[key]) {
       const ref = new StorageRef(this, path);
       this.refs[key] = ref;
@@ -74,13 +85,14 @@ export default class Storage extends Base {
    * @param  {object} metadata An object containing metadata
    * @return {Promise}
    */
-  uploadFile(name, filepath, metadata={}, cb) {
+  uploadFile(name: string, filepath: string, metadata: Object={}, cb: (evt: Object) => Object): Promise<Object> {
+    this.log.debug('uploadFile(', filepath, ') -> ', name);
     let callback = cb;
     if (!callback || typeof callback !== 'function') {
-      callback = (evt) => {}
+      callback = (evt: Object) => ({});
     }
 
-    filepath = filepath.replace("file://", "");
+    filepath = filepath.replace('file://', '');
 
     const listeners = [];
     listeners.push(this._addListener('upload_progress', callback));
@@ -88,29 +100,30 @@ export default class Storage extends Base {
     listeners.push(this._addListener('upload_resumed', callback));
     return promisify('uploadFile', FirestackStorage)(this.storageUrl, name, filepath, metadata)
       .then((res) => {
-        listeners.forEach(this._removeListener);
+        listeners.forEach(listener => listener.remove());
         return res;
+      })
+      .catch(err => {
+        this.log.error('Error uploading file ', name, ' to ', filepath, '.  Error: ', err);
+        throw err;
       });
   }
 
-  getRealPathFromURI(uri) {
+  getRealPathFromURI(uri: string): Promise<string> {
     return promisify('getRealPathFromURI', FirestackStorage)(uri);
   }
 
-  _addListener(evt, cb) {
-    return FirestackStorageEvt.addListener(evt, cb);
-  }
-
-  _removeListener(evt) {
-    return FirestackStorageEvt.removeListener(evt);
+  _addListener(evt: string, cb: (evt: Object) => Object): {remove: () => void} {
+    let listener = FirestackStorageEvt.addListener(evt, cb);
+    return listener;
   }
 
-  setStorageUrl(url) {
+  setStorageUrl(url: string): void {
     // return promisify('setStorageUrl', FirestackStorage)(url);
     this.storageUrl = `gs://${url}`;
   }
 
-  _pathKey(...path) {
+  _pathKey(...path: Array<string>): string {
     return path.join('-');
   }
 
@@ -126,7 +139,7 @@ export default class Storage extends Base {
       'FILETYPE_DIRECTORY': FirestackStorage.FILETYPE_DIRECTORY
   };
 
-  get namespace() {
+  get namespace(): string {
     return 'firestack:storage'
   }
 }
diff --git a/lib/utils/window-or-global.js b/lib/utils/window-or-global.js
index 7b64020..c19a003 100644
--- a/lib/utils/window-or-global.js
+++ b/lib/utils/window-or-global.js
@@ -2,4 +2,4 @@
 // https://github.com/purposeindustries/window-or-global
 module.exports = (typeof self === 'object' && self.self === self && self) ||
   (typeof global === 'object' && global.global === global && global) ||
-  {}
\ No newline at end of file
+  this