js: change db error to match firebase web sdk error

.watchmanconfig

@@ -1,6 +1,7 @@
 {
   "ignore_dirs": [
     ".git",
+    "node_modules",
     "android/build",
     "android/.idea",
     "android/.gradle",

lib/modules/database/index.js

@@ -84,6 +84,7 @@ export default class Database extends Base {
     if (!this.subscriptions[handle]) this.subscriptions[handle] = {};
     if (!this.subscriptions[handle][eventName]) this.subscriptions[handle][eventName] = [];
     this.subscriptions[handle][eventName].push(cb);
+
     if (errorCb) {
       if (!this.errorSubscriptions[handle]) this.errorSubscriptions[handle] = [];
       this.errorSubscriptions[handle].push(errorCb);
@@ -220,10 +221,10 @@ export default class Database extends Base {
    */
   _toFirebaseError(error) {
     const { path, message, modifiers, code, details } = error;
-    let firebaseMessage = `FirebaseError: ${message}`;
+    let firebaseMessage = `FirebaseError: ${message.toLowerCase().replace(/\s/g, '_')}`;
 
     if (path) {
-      firebaseMessage = `${firebaseMessage}\r\nPath: /${path}\r\n`;
+      firebaseMessage = `${firebaseMessage} at /${path}\r\n`;
     }
 
     const firebaseError = new Error(firebaseMessage);

lib/modules/database/reference.js

@@ -77,12 +77,12 @@ export default class Reference extends ReferenceBase {
    */
   push(value: any, onComplete: Function) {
     if (value === null || value === undefined) {
-      const _path = this.path + '/' + generatePushID(this.db.serverTimeOffset);
-      return new Reference(this.db, _path);
+      return new Reference(this.db, `${this.path}/${generatePushID(this.db.serverTimeOffset)}`);
     }
 
     const path = this._dbPath();
     const _value = this._serializeAnyType(value);
+
     return promisify('push', FirebaseDatabase)(path, _value)
       .then(({ ref }) => {
         const newRef = new Reference(this.db, ref);
@@ -102,7 +102,7 @@ export default class Reference extends ReferenceBase {
    * @param context TODO
    * @returns {*}
    */
-  on(eventType: string, successCallback: () => any, failureCallback: () => any, context) {
+  on(eventType: string, successCallback: () => any, failureCallback: () => any) {
     if (!isFunction(successCallback)) throw new Error('The specified callback must be a function');
     if (failureCallback && !isFunction(failureCallback)) throw new Error('The specified error callback must be a function');
     const path = this._dbPath();
@@ -280,14 +280,27 @@ export default class Reference extends ReferenceBase {
     return newRef;
   }
 
+  /**
+   *
+   * @returns {Disconnect}
+   */
   onDisconnect() {
     return new Disconnect(this.path);
   }
 
+  /**
+   * Get a specified child
+   * @param path
+   * @returns {Reference}
+   */
   child(path: string) {
-    return new Reference(this.db, this.path + '/' + path);
+    return new Reference(this.db, `${this.path}/${path}`);
   }
 
+  /**
+   * Return the ref as a path string
+   * @returns {string}
+   */
   toString(): string {
     return this._dbPath();
   }