FocusManager

Defined in: packages/query-core/src/focusManager.ts:14

The FocusManager manages the focus state within TanStack Query.

It can be used to change the default event listeners or to manually change the focus state.

Extends

• Subscribable<Listener>

Methods

hasListeners()

hasListeners(): boolean;

Defined in: packages/query-core/src/subscribable.ts:43

Returns true while at least one listener is registered, false once they have all unsubscribed.

Returns

boolean

true if at least one listener is registered.

Inherited from

Subscribable.hasListeners

isFocused()

isFocused(): boolean;

Defined in: packages/query-core/src/focusManager.ts:130

isFocused can be used to get the current focus state.

Returns

boolean

The focus state set with setFocused, or otherwise whether the document is visible.

onFocus()

onFocus(): void;

Defined in: packages/query-core/src/focusManager.ts:119

onFocus notifies all subscribed listeners with the current focus state.

Returns

void

setEventListener()

setEventListener(setup: SetupFn): void;

Defined in: packages/query-core/src/focusManager.ts:78

setEventListener can be used to set a custom event listener that will be used to determine the focus state. The provided setup function receives a setFocused callback: call it with a boolean to manually set the focus state, or with no arguments to re-evaluate the current focus state and notify subscribers.

Parameters

setup

SetupFn

Receives the setFocused callback, registers the event listener, and may return a cleanup function that is called when the listener is replaced or no longer needed.

Returns

void

Example

import { focusManager } from '@tanstack/query-core'

focusManager.setEventListener((handleFocus) => {
  const listener = () => handleFocus()
  // Listen to visibilitychange
  if (typeof window !== 'undefined' && window.addEventListener) {
    window.addEventListener('visibilitychange', listener, false)
  }

  return () => {
    // Be sure to unsubscribe if a new handler is set
    window.removeEventListener('visibilitychange', listener)
  }
})

setFocused()

setFocused(focused?: boolean): void;

Defined in: packages/query-core/src/focusManager.ts:108

setFocused can be used to manually set the focus state. Set undefined to fall back to the default focus check.

Parameters

focused?

boolean

The focus state, or undefined to use the default focus check.

Returns

void

Example

import { focusManager } from '@tanstack/query-core'

// Set focused
focusManager.setFocused(true)

// Set unfocused
focusManager.setFocused(false)

// Fallback to the default focus check
focusManager.setFocused(undefined)

subscribe()

subscribe(listener: Listener): () => void;

Defined in: packages/query-core/src/subscribable.ts:28

Registers a listener to be called on every update this object notifies about. Returns a function that removes the listener again — call it to stop listening. The base class never drops a listener on its own, though some subclasses clear all of theirs in destroy().

Parameters

listener

Listener

Called on each update, with whatever the subclass passes to its subscribers.

Returns

A function that removes the listener.

() => void

Example

const unsubscribe = subscribable.subscribe(() => {
  // react to the update
})

unsubscribe()

Inherited from

Subscribable.subscribe