Reading data

Sometimes you just need to fetch data once without subscribing to ongoing changes. The Lark SDK provides two equivalent methods for this.

`once(eventType)`

Reads data at a reference and returns a promise that resolves with a DataSnapshot:

import { LarkDatabase } from "@lark-sh/client";

const db = new LarkDatabase("my-project/my-database", { anonymous: true });

const snapshot = await db.ref("users/alice").once("value");

console.log(snapshot.val());
// { name: "Alice", score: 42, online: true }

`get()`

An alias for once('value'). Same behavior, shorter syntax:

const snapshot = await db.ref("users/alice").get();

console.log(snapshot.val());
// { name: "Alice", score: 42, online: true }

Working with snapshots

Both methods return a DataSnapshot. Here are the key properties and methods:

`snapshot.val()`

Returns the data as a JavaScript value (object, array, string, number, boolean, or null):

const snapshot = await db.ref("users/alice").get();
const user = snapshot.val(); // { name: "Alice", score: 42 }

`snapshot.exists()`

Returns true if data exists at this location, false if it’s null:

const snapshot = await db.ref("users/nonexistent").get();

if (snapshot.exists()) {
  console.log(snapshot.val());
} else {
  console.log("No data here");
}

`snapshot.key`

The key (last path segment) of the location this snapshot represents:

const snapshot = await db.ref("users/alice").get();
console.log(snapshot.key); // "alice"

If you need data that stays up to date as it changes, use real-time subscriptions instead. once() and get() fetch a single point-in-time snapshot and don’t update afterward.

Getting started

Guides

API reference

Reading data

Reading data

`once(eventType)`

`get()`

Working with snapshots

`snapshot.val()`

`snapshot.exists()`

`snapshot.key`

​Reading data

​once(eventType)

​get()

​Working with snapshots

​snapshot.val()

​snapshot.exists()

​snapshot.key

Reading data

`once(eventType)`

`get()`

Working with snapshots

`snapshot.val()`

`snapshot.exists()`

`snapshot.key`