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Getting the height of an element in React:

1. Sets the attribute on the element ref.
2. In useLayoutEffectthe hook, update the state variable for the height.
3. Use clientHeightthe property to get the height of an element.

import {useLayoutEffect, useRef, useState} from 'react';

export default function App() {
  const ref = useRef(null);

  const [height, setHeight] = useState(0);
  const [width, setWidth] = useState(0);

  useLayoutEffect(() => {
    setHeight(ref.current.clientHeight);
    setWidth(ref.current.clientWidth);
  }, []);

  return (
    <div ref={ref}>
      <h2>Height: {height}</h2>

      <h2>Width: {width}</h2>
    </div>
  );
}

useRef()The hook can be passed an initial value as an argument. The hook returns a mutable refobject whose .currentproperties are initialized to the passed argument.

Note that we have to access the currentref property of the object in order to access the element on which we set the ref attribute .div

When we refpass the attribute to an element, for example <div ref={myRef} />, React sets the .currentref property of the object to the corresponding DOM node.

We pass an empty dependencies array to useLayoutEffectthe hook, so it will only run when the component is mounted.

useLayoutEffect(() => {
  setHeight(ref.current.clientHeight);
  setWidth(ref.current.clientWidth);
}, []);

useLayoutEffectHook is useEffectthe same as , but is fired synchronously after all DOM mutations.

useLayoutEffectHooks are usually used to read the layout from the DOM.

We used useLayoutEffectthe hook because we need to wait for a ref to be set on the element and for the element to be rendered before accessing its clientHeight and clientWidth properties.

The clientHeight property returns the intrinsic height of the element in pixels. It includes padding but excludes borders, margins, and the horizontal scroll bar (if present).

The clientWidth property returns the width of the element in pixels, including padding but excluding borders, margins, and the vertical scroll bar (if any).

Alternatively, we can use the offsetHeight property.

useLayoutEffect(() => {
  setHeight(ref.current.offsetHeight);
  setWidth(ref.current.offsetWidth);
}, []);

The offsetHeight property returns the height of an element in pixels, including vertical padding and border.

The offsetWidth property returns the width of an element in pixels, including any borders, padding, and vertical scroll bar (if any).