LockManager: query() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2022.

Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.

Note: This feature is available in Web Workers.

The query() method of the LockManager interface returns a Promise that resolves with an object containing information about held and pending locks.

Syntax

js
query()

Parameters

None.

Return value

A Promise that resolves with an object containing a snapshot of the LockManager state. The object has the following properties:

held

An array of LockInfo objects for held locks.

pending

An array of LockInfo objects for pending lock requests.

The LockInfo object can have the following properties:

name

The name passed to LockManager.request() when the lock was requested.

mode

The access mode passed to LockManager.request() when the lock was requested. The mode is either "exclusive" or "shared".

clientId

The unique identity of the context where LockManager.request() is called. This is the same value as Client.id.

Exceptions

This method may return a promise rejected with a DOMException of one of the following types:

InvalidStateError DOMException

Thrown if the environments document is not fully active.

SecurityError DOMException

Thrown if a lock manager cannot be obtained for the current environment.

Examples

js
const state = await navigator.locks.query();
for (const lock of state.held) {
  console.log(`held lock: name ${lock.name}, mode ${lock.mode}`);
}
for (const request of state.pending) {
  console.log(`requested lock: name ${request.name}, mode ${request.mode}`);
}

Specifications

Specification
Web Locks API
# api-lock-manager-query

Browser compatibility