usePreviousState()

function usePreviousState<T>(state, initialValue?): T | undefined;

Defined in: previous.ts:31

React hook for getting the previous state value.

Type Parameters

Type Parameter	Description
T	Type of the state value.

Parameters

Parameter	Type	Description
state	T	Current state value to track.
initialValue?	T	Optional initial value for the previous state. If not provided, the previous state will be undefined on the first render.

Returns

T | undefined

Previous state value of type T or undefined if it's the first render and no initial value is provided.

Example

function MyComponent () {
  const [count, setCount] = useState(0);
  const prevCount = usePreviousState(count);

  return (
    <>
      <p>Current count: {count}</p>
      <p>Previous count: {prevCount}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </>
  )
}

Since

1.0.0

Author

Simon Kovtyk