Live queries

Live queries allow your application to receive real-time notifications whenever records in the database are created, updated, or deleted. The JavaScript SDK provides two approaches: managed live queries that the SDK controls and automatically restarts on reconnect, and unmanaged live queries that you create via SurrealQL and subscribe to manually.

API References

Creating a managed live query

The .live() method creates a managed live query subscription. The SDK handles the lifecycle of the query, including automatically restarting it when the connection reconnects. The provided Table determines the records to listen to.

import { Table } from 'surrealdb';

const live = await db.live(new Table('users'));

Much like the .select() method, you can chain multiple methods to configure the live query before executing it. This includes enabling diff results, selecting specific fields, and filtering the records to listen to.

import { gt } from 'surrealdb';

const live = await db.live(new Table('users'))
    .diff()
    .fields('name', 'email', 'age')
    .where(gt('age', 18));

Listening with a callback

Use .subscribe() on the returned live query to register a callback. The callback receives the action, the result record, and the record ID.

live.subscribe((action, result, record) => {
    switch (action) {
        case 'CREATE':
            console.log('New user:', result);
            break;
        case 'UPDATE':
            console.log('Updated user:', record, result);
            break;
        case 'DELETE':
            console.log('Deleted user:', record);
            break;
    }
});

Iterating messages with async iteration

Live queries also support the for await...of pattern, which yields each message as an object with action and value properties.

for await (const { action, value } of live) {
    console.log(`${action}:`, value);
}

Creating an unmanaged live query

If you need to start a live query using SurrealQL (for example, with a custom WHERE clause), you can execute a LIVE SELECT statement and then subscribe to it using .liveOf(). Unmanaged queries are not automatically restarted on reconnect.

const [id] = await db.query('LIVE SELECT * FROM users WHERE active = true');
const live = db.liveOf(id);

live.subscribe((action, result, record) => {
    console.log(action, result);
});

Handling live query actions

Every live query message has an action that indicates what happened to the record:

Stopping a live query

Call .kill() to stop a live query and unsubscribe all listeners. This releases resources on both the client and the server.

await live.kill();

Automatic restart on reconnect

Managed live queries created with .live() are automatically restarted when the SDK reconnects to the database after a connection drop. This means your application will continue receiving updates without any manual intervention.

Unmanaged live queries created via LIVE SELECT and .liveOf() are not automatically restarted. If you need reconnection resilience with custom queries, prefer using a managed live query or re-subscribing manually by listening to the connected event.

Checking for live query support

Live queries require a WebSocket-based engine. Before creating a live query, you can verify that the current connection supports them.

import { Features } from 'surrealdb';

if (db.isFeatureSupported(Features.LiveQueries)) {
    const live = await db.live(new Table('users'));
}

Learn more

• Live query API reference for detailed method signatures

• Connecting to SurrealDB for WebSocket connection setup

• LIVE SELECT for the SurrealQL live query syntax