• firebase.
• database.
• Database

The Firebase Database service interface.

Do not call this constructor directly. Instead, use firebase.database().

See Installation & Setup in JavaScript for a full guide on how to use the Firebase Database service.

Index

Properties

• INTERNAL
• app

Methods

• goOffline
• goOnline
• ref
• refFromURL
• useEmulator

Properties

INTERNAL

INTERNAL: { forceLongPolling: () => void; forceWebSockets: () => void }

Additional methods for debugging and special cases.

Type declaration

• forceLongPolling: () => void

  Force the use of long polling instead of WebSockets. This will be ignored if the WebSocket protocol is used in databaseURL.

  • • (): void

    • Returns void

• forceWebSockets: () => void

  Force the use of WebSockets instead of long polling.

  • • (): void

    • Returns void

app

app: App

The app associated with the Database service instance.

example

var app = database.app;

Methods

goOffline

• goOffline ( ) : any

• Disconnects from the server (all Database operations will be completed offline).

  The client automatically maintains a persistent connection to the Database server, which will remain active indefinitely and reconnect when disconnected. However, the goOffline() and goOnline() methods may be used to control the client connection in cases where a persistent connection is undesirable.

  While offline, the client will no longer receive data updates from the Database. However, all Database operations performed locally will continue to immediately fire events, allowing your application to continue behaving normally. Additionally, each operation performed locally will automatically be queued and retried upon reconnection to the Database server.

  To reconnect to the Database and begin receiving remote events, see goOnline().

  example

  firebase.database().goOffline();

  Returns any

goOnline

• goOnline ( ) : any

• Reconnects to the server and synchronizes the offline Database state with the server state.

  This method should be used after disabling the active connection with goOffline(). Once reconnected, the client will transmit the proper data and fire the appropriate events so that your client "catches up" automatically.

  example

  firebase.database().goOnline();

  Returns any

ref

• ref ( path ? :  string ) : Reference

• Returns a Reference representing the location in the Database corresponding to the provided path. If no path is provided, the Reference will point to the root of the Database.

  example

  // Get a reference to the root of the Database
  var rootRef = firebase.database().ref();

  example

  // Get a reference to the /users/ada node
  var adaRef = firebase.database().ref("users/ada");
  // The above is shorthand for the following operations:
  //var rootRef = firebase.database().ref();
  //var adaRef = rootRef.child("users/ada");

  Parameters

  • Optional path: string

    Optional path representing the location the returned Reference will point. If not provided, the returned Reference will point to the root of the Database.

  Returns Reference

  If a path is provided, a Reference pointing to the provided path. Otherwise, a Reference pointing to the root of the Database.

refFromURL

• refFromURL ( url :  string ) : Reference

• Returns a Reference representing the location in the Database corresponding to the provided Firebase URL.

  An exception is thrown if the URL is not a valid Firebase Database URL or it has a different domain than the current Database instance.

  Note that all query parameters (orderBy, limitToLast, etc.) are ignored and are not applied to the returned Reference.

  example

  // Get a reference to the root of the Database
  var rootRef = firebase.database().ref("https://<DATABASE_NAME>.firebaseio.com");

  example

  // Get a reference to the /users/ada node
  var adaRef = firebase.database().ref("https://<DATABASE_NAME>.firebaseio.com/users/ada");

  Parameters

  • url: string

    The Firebase URL at which the returned Reference will point.

  Returns Reference

  A Reference pointing to the provided Firebase URL.

useEmulator

• useEmulator ( host :  string ,  port :  number ,  options ? :  { mockUserToken ?: EmulatorMockTokenOptions | string } ) : void

• Modify this instance to communicate with the Realtime Database emulator.

  Note: This method must be called before performing any other operation.

  Parameters

  • host: string

    the emulator host (ex: localhost)

  • port: number

    the emulator port (ex: 8080)

  • Optional options: { mockUserToken?: EmulatorMockTokenOptions | string }

    • Optional mockUserToken?: EmulatorMockTokenOptions | string

      the mock auth token to use for unit testing Security Rules

  Returns void