|
| 1 | +/** |
| 2 | + * WordPress dependencies |
| 3 | + */ |
| 4 | +import { useRef } from '@wordpress/element'; |
| 5 | +/** |
| 6 | + * Internal dependencies |
| 7 | + */ |
| 8 | +import useEvent from '../use-event'; |
| 9 | +import type { ObservedSize } from './_legacy'; |
| 10 | +import _useLegacyResizeObserver from './_legacy'; |
| 11 | +/** |
| 12 | + * External dependencies |
| 13 | + */ |
| 14 | +import type { ReactElement } from 'react'; |
| 15 | + |
| 16 | +// This is the current implementation of `useResizeObserver`. |
| 17 | +// |
| 18 | +// The legacy implementation is still supported for backwards compatibility. |
| 19 | +// This is achieved by overloading the exported function with both signatures, |
| 20 | +// and detecting which API is being used at runtime. |
| 21 | +function _useResizeObserver< T extends HTMLElement >( |
| 22 | + callback: ResizeObserverCallback, |
| 23 | + resizeObserverOptions: ResizeObserverOptions = {} |
| 24 | +): ( element?: T | null ) => void { |
| 25 | + const callbackEvent = useEvent( callback ); |
| 26 | + |
| 27 | + const observedElementRef = useRef< T | null >(); |
| 28 | + const resizeObserverRef = useRef< ResizeObserver >(); |
| 29 | + return useEvent( ( element?: T | null ) => { |
| 30 | + if ( element === observedElementRef.current ) { |
| 31 | + return; |
| 32 | + } |
| 33 | + observedElementRef.current = element; |
| 34 | + |
| 35 | + // Set up `ResizeObserver`. |
| 36 | + resizeObserverRef.current ??= new ResizeObserver( callbackEvent ); |
| 37 | + const { current: resizeObserver } = resizeObserverRef; |
| 38 | + |
| 39 | + // Unobserve previous element. |
| 40 | + if ( observedElementRef.current ) { |
| 41 | + resizeObserver.unobserve( observedElementRef.current ); |
| 42 | + } |
| 43 | + |
| 44 | + // Observe new element. |
| 45 | + if ( element ) { |
| 46 | + resizeObserver.observe( element, resizeObserverOptions ); |
| 47 | + } |
| 48 | + } ); |
| 49 | +} |
| 50 | + |
| 51 | +/** |
| 52 | + * Sets up a [`ResizeObserver`](https://developer.mozilla.org/en-US/docs/Web/API/Resize_Observer_API) |
| 53 | + * for an HTML or SVG element. |
| 54 | + * |
| 55 | + * Pass the returned setter as a callback ref to the React element you want |
| 56 | + * to observe, or use it in layout effects for advanced use cases. |
| 57 | + * |
| 58 | + * @example |
| 59 | + * |
| 60 | + * ```tsx |
| 61 | + * const setElement = useResizeObserver( |
| 62 | + * ( resizeObserverEntries ) => console.log( resizeObserverEntries ), |
| 63 | + * { box: 'border-box' } |
| 64 | + * ); |
| 65 | + * <div ref={ setElement } />; |
| 66 | + * |
| 67 | + * // The setter can be used in other ways, for example: |
| 68 | + * useLayoutEffect( () => { |
| 69 | + * setElement( document.querySelector( `data-element-id="${ elementId }"` ) ); |
| 70 | + * }, [ elementId ] ); |
| 71 | + * ``` |
| 72 | + * |
| 73 | + * @param callback The `ResizeObserver` callback - [MDN docs](https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver/ResizeObserver#callback). |
| 74 | + * @param options Options passed to `ResizeObserver.observe` when called - [MDN docs](https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver/observe#options). Changes will be ignored. |
| 75 | + */ |
| 76 | +export default function useResizeObserver< T extends Element >( |
| 77 | + /** |
| 78 | + * The `ResizeObserver` callback - [MDN docs](https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver/ResizeObserver#callback). |
| 79 | + */ |
| 80 | + callback: ResizeObserverCallback, |
| 81 | + /** |
| 82 | + * Options passed to `ResizeObserver.observe` when called - [MDN docs](https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver/observe#options). Changes will be ignored. |
| 83 | + */ |
| 84 | + options?: ResizeObserverOptions |
| 85 | +): ( element?: T | null ) => void; |
| 86 | + |
| 87 | +/** |
| 88 | + * **This is a legacy API and should not be used.** |
| 89 | + * |
| 90 | + * @deprecated Use the other `useResizeObserver` API instead: `const ref = useResizeObserver( ( entries ) => { ... } )`. |
| 91 | + * |
| 92 | + * Hook which allows to listen to the resize event of any target element when it changes size. |
| 93 | + * _Note: `useResizeObserver` will report `null` sizes until after first render. |
| 94 | + * |
| 95 | + * @example |
| 96 | + * |
| 97 | + * ```js |
| 98 | + * const App = () => { |
| 99 | + * const [ resizeListener, sizes ] = useResizeObserver(); |
| 100 | + * |
| 101 | + * return ( |
| 102 | + * <div> |
| 103 | + * { resizeListener } |
| 104 | + * Your content here |
| 105 | + * </div> |
| 106 | + * ); |
| 107 | + * }; |
| 108 | + * ``` |
| 109 | + */ |
| 110 | +export default function useResizeObserver(): [ ReactElement, ObservedSize ]; |
| 111 | + |
| 112 | +export default function useResizeObserver< T extends HTMLElement >( |
| 113 | + callback?: ResizeObserverCallback, |
| 114 | + options: ResizeObserverOptions = {} |
| 115 | +): ( ( element?: T | null ) => void ) | [ ReactElement, ObservedSize ] { |
| 116 | + return callback |
| 117 | + ? _useResizeObserver( callback, options ) |
| 118 | + : _useLegacyResizeObserver(); |
| 119 | +} |
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