| import { Subscribable } from './subscribable' |
| import { isServer } from './utils' |
|
|
| type Listener = (focused: boolean) => void |
|
|
| type SetupFn = ( |
| setFocused: (focused?: boolean) => void, |
| ) => (() => void) | undefined |
|
|
| export class FocusManager extends Subscribable<Listener> { |
| #focused?: boolean |
| #cleanup?: () => void |
|
|
| #setup: SetupFn |
|
|
| constructor() { |
| super() |
| this.#setup = (onFocus) => { |
| |
| |
| if (!isServer && window.addEventListener) { |
| const listener = () => onFocus() |
| |
| window.addEventListener('visibilitychange', listener, false) |
|
|
| return () => { |
| |
| window.removeEventListener('visibilitychange', listener) |
| } |
| } |
| return |
| } |
| } |
|
|
| protected onSubscribe(): void { |
| if (!this.#cleanup) { |
| this.setEventListener(this.#setup) |
| } |
| } |
|
|
| protected onUnsubscribe() { |
| if (!this.hasListeners()) { |
| this.#cleanup?.() |
| this.#cleanup = undefined |
| } |
| } |
|
|
| setEventListener(setup: SetupFn): void { |
| this.#setup = setup |
| this.#cleanup?.() |
| this.#cleanup = setup((focused) => { |
| if (typeof focused === 'boolean') { |
| this.setFocused(focused) |
| } else { |
| this.onFocus() |
| } |
| }) |
| } |
|
|
| setFocused(focused?: boolean): void { |
| const changed = this.#focused !== focused |
| if (changed) { |
| this.#focused = focused |
| this.onFocus() |
| } |
| } |
|
|
| onFocus(): void { |
| const isFocused = this.isFocused() |
| this.listeners.forEach((listener) => { |
| listener(isFocused) |
| }) |
| } |
|
|
| isFocused(): boolean { |
| if (typeof this.#focused === 'boolean') { |
| return this.#focused |
| } |
|
|
| |
| |
| return globalThis.document?.visibilityState !== 'hidden' |
| } |
| } |
|
|
| export const focusManager = new FocusManager() |
|
|
