##<firebase-app>

The firebase-app element is used for initializing and configuring your connection to firebase.

##<firebase-auth>

firebase-auth is a wrapper around the Firebase authentication API. It notifies successful authentication, provides user information, and handles different types of authentication including anonymous, email / password, and several OAuth workflows.

Example Usage:

<firebase-app auth-domain="polymerfire-test.firebaseapp.com"
  database-url="https://polymerfire-test.firebaseio.com/"
  api-key="AIzaSyDTP-eiQezleFsV2WddFBAhF_WEzx_8v_g">
</firebase-app>
<firebase-auth id="auth" user="{{user}}" provider="google" on-error="handleError">
</firebase-auth>

The firebase-app element initializes app in firebase-auth (see firebase-app documentation for more information), but an app name can simply be specified at firebase-auth's app-name property instead.

JavaScript sign-in calls can then be made to the firebase-auth object to attempt authentication, e.g.:

this.$.auth.signInWithPopup()
    .then(function(response) {// successful authentication response here})
    .catch(function(error) {// unsuccessful authentication response here});

This popup sign-in will then attempt to sign in using Google as an OAuth provider since there was no provider argument specified and since "google" was defined as the default provider.

##<firebase-document>

The firebase-document element is an easy way to interact with a firebase location as an object and expose it to the Polymer databinding system.

For example:

<firebase-document
  path="/users/{{userId}}/notes/{{noteId}}"
  data="{{noteData}}">
</firebase-document>

This fetches the noteData object from the firebase location at /users/${userId}/notes/${noteId} and exposes it to the Polymer databinding system. Changes to noteData will likewise be, sent back up and stored.

<firebase-document> needs some information about how to talk to Firebase. Set this configuration by adding a <firebase-app> element anywhere in your app.

##<firebase-query>

firebase-query combines the given properties into query options that generate a query, a request for a filtered, ordered, immutable set of Firebase data. The results of this Firebase query are then synchronized into the data parameter.

Example usage:

<firebase-query
    id="query"
    app-name="notes"
    path="/notes/[[uid]]"
    data="{{data}}">
</firebase-query>

<template is="dom-repeat" items="{{data}}" as="note">
  <sticky-note note-data="{{note}}"></sticky-note>
</template>

<script>
Polymer({
  properties: {
    uid: String,
    data: {
      type: Object,
      observer: 'dataChanged'
    }
  },

  dataChanged: function (newData, oldData) {
    // do something when the query returns values
  }
});
</script>