src/hooks/usePrevious.ts
/** https://usehooks.com/usePrevious/ **/
import { useEffect, useRef } from 'react';
import type { MutableRefObject } from 'react';
export default function usePrevious<T>(value: T): MutableRefObject<T | undefined>['current'] {
// The ref object is a generic container whose current property is mutable ...
// ... and can hold any value, similar to an instance property on a class
const ref = useRef<T>();
// Store current value in ref
useEffect(() => {
ref.current = value;
}, [value]); // Only re-run if value changes
// Return previous value (happens before update in useEffect above)
return ref.current;
}