GoScrobble/web/node_modules/@restart/hooks/esm/usePrevious.js

26 lines
607 B
JavaScript

import { useEffect, useRef } from 'react';
/**
* Store the last of some value. Tracked via a `Ref` only updating it
* after the component renders.
*
* Helpful if you need to compare a prop value to it's previous value during render.
*
* ```ts
* function Component(props) {
* const lastProps = usePrevious(props)
*
* if (lastProps.foo !== props.foo)
* resetValueFromProps(props.foo)
* }
* ```
*
* @param value the value to track
*/
export default function usePrevious(value) {
var ref = useRef(null);
useEffect(function () {
ref.current = value;
});
return ref.current;
}