Functions

Classes

database.instance()

Registers a function that triggers on events from a specific Firebase Realtime Database instance.

Use this method together withref to specify the instance on which to watch for database events. For example:firebase.database.instance('my-app-db-2').ref('/foo/bar')

Note thatfunctions.database.ref used withoutinstance watches the *default* instance for events.

Signature:

exportdeclarefunctioninstance(instance:string):InstanceBuilder;

Parameters

Returns:

InstanceBuilder

Firebase Realtime Database instance builder interface.

database.ref()

Registers a function that triggers on Firebase Realtime Database write events.

This method behaves very similarly to the method of the same name in the client and Admin Firebase SDKs. Any change to the Database that affects the data at or below the providedpath will fire an event in Cloud Functions.

There are three important differences between listening to a Realtime Database event in Cloud Functions and using the Realtime Database in the client and Admin SDKs:

1. Cloud Functions allows wildcards in thepath name. Anypath component in curly brackets ({}) is a wildcard that matches all strings. The value that matched a certain invocation of a Cloud Function is returned as part of the [EventContext.params](cloud_functions_eventcontext.html#params object. For example,ref("messages/{messageId}") matches changes at/messages/message1 or/messages/message2, resulting inevent.params.messageId being set to"message1" or"message2", respectively.

2. Cloud Functions do not fire an event for data that already existed before the Cloud Function was deployed.

3. Cloud Function events have access to more information, including a snapshot of the previous event data and information about the user who triggered the Cloud Function.

Signature:

exportdeclarefunctionref<Refextendsstring>(path:Ref):RefBuilder<Ref>;

Parameters

Returns:

RefBuilder<Ref>

Firebase Realtime Database builder interface.