useElementSize()

1import { useCallback, useState } from 'react'
2
3import { useEventListener, useIsomorphicLayoutEffect } from 'usehooks-ts'
4
5interface Size {
6  width: number
7  height: number
8}
9
10function useElementSize<T extends HTMLElement = HTMLDivElement>(): [
11  (node: T | null) => void,
12  Size,
13] {
14  // Mutable values like 'ref.current' aren't valid dependencies
15  // because mutating them doesn't re-render the component.
16  // Instead, we use a state as a ref to be reactive.
17  const [ref, setRef] = useState<T | null>(null)
18  const [size, setSize] = useState<Size>({
19    width: 0,
20    height: 0,
21  })
22
23  // Prevent too many rendering using useCallback
24  const handleSize = useCallback(() => {
25    setSize({
26      width: ref?.offsetWidth || 0,
27      height: ref?.offsetHeight || 0,
28    })
29
30    // eslint-disable-next-line react-hooks/exhaustive-deps
31  }, [ref?.offsetHeight, ref?.offsetWidth])
32
33  useEventListener('resize', handleSize)
34
35  useIsomorphicLayoutEffect(() => {
36    handleSize()
37    // eslint-disable-next-line react-hooks/exhaustive-deps
38  }, [ref?.offsetHeight, ref?.offsetWidth])
39
40  return [setRef, size]
41}
42
43export default useElementSize

1import { useState } from 'react'
2
3import { useElementSize } from 'usehooks-ts'
4
5export default function Component() {
6  const [isVisible, setVisible] = useState(true)
7  const [squareRef, { width, height }] = useElementSize()
8
9  const toggleVisibility = () => setVisible(x => !x)
10
11  return (
12    <>
13      <p>{`The square width is ${width}px and height ${height}px`}</p>
14      <p>Try, resize your window and-or click on the button.</p>
15
16      <button onClick={toggleVisibility}>
17        {isVisible ? 'Hide' : 'Show'} square
18      </button>
19
20      {isVisible && (
21        <div
22          ref={squareRef}
23          style={{
24            width: '50%',
25            paddingTop: '50%',
26            backgroundColor: 'aquamarine',
27            margin: 'auto',
28          }}
29        />
30      )}
31    </>
32  )
33}