File size: 3,376 Bytes
1e92f2d | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 | import { useCallback, useState } from 'react';
const EPS = 1;
/**
* TODO this documentation does not reflect what this hook is doing, update it.
* Stores the `offsetHeight`, `offsetLeft`, `offsetTop`, and `offsetWidth` of a DOM element.
*/
export type ElementOffset = {
/**
* Height of an element, including vertical padding and borders, as an integer.
*
* Typically, offsetHeight is a measurement in pixels of the element's CSS height, including any borders, padding, and horizontal scrollbars (if rendered). It does not include the height of pseudo-elements such as ::before or ::after
*
* https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/offsetHeight
*/
height: number;
/**
* Number of pixels that the upper left corner of the current element is offset to the left within the HTMLElement.offsetParent node
*
* https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/offsetLeft
*/
left: number;
/**
* Distance from the outer border of the current element (including its margin) to the top padding edge of the offsetParent, the closest positioned ancestor element.
*
* https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/offsetTop
*/
top: number;
/**
* Layout width of an element as an integer.
*
* Typically, offsetWidth is a measurement in pixels of the element's CSS width, including any borders, padding, and vertical scrollbars (if rendered). It does not include the width of pseudo-elements such as ::before or ::after.
*
* https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/offsetWidth
*/
width: number;
};
export type SetElementOffset = (node: HTMLElement | null) => void;
/**
* Use this to listen to element layout changes.
*
* Very useful for reading actual sizes of DOM elements relative to the viewport.
*
* @param extraDependencies use this to trigger new DOM dimensions read when any of these change. Good for things like payload and label, that will re-render something down in the children array, but you want to read the layout box of a parent.
* @returns [lastElementOffset, updateElementOffset] most recent value, and setter. Pass the setter to a DOM element ref like this: `<div ref={updateElementOffset}>`
*/
export function useElementOffset(extraDependencies: ReadonlyArray<unknown> = []): [ElementOffset, SetElementOffset] {
const [lastBoundingBox, setLastBoundingBox] = useState<ElementOffset>({ height: 0, left: 0, top: 0, width: 0 });
const updateBoundingBox = useCallback(
(node: HTMLDivElement | null) => {
if (node != null) {
const rect = node.getBoundingClientRect();
const box: ElementOffset = {
height: rect.height,
left: rect.left,
top: rect.top,
width: rect.width,
};
if (
Math.abs(box.height - lastBoundingBox.height) > EPS ||
Math.abs(box.left - lastBoundingBox.left) > EPS ||
Math.abs(box.top - lastBoundingBox.top) > EPS ||
Math.abs(box.width - lastBoundingBox.width) > EPS
) {
setLastBoundingBox({ height: box.height, left: box.left, top: box.top, width: box.width });
}
}
},
[lastBoundingBox.width, lastBoundingBox.height, lastBoundingBox.top, lastBoundingBox.left, ...extraDependencies],
);
return [lastBoundingBox, updateBoundingBox];
}
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