# React usePrevious hook

Canonical: https://www.wiki.jodisand.me/snippets/react/useprevious/


Stores the previous state or props.

- Create a custom hook that takes a `value`.
- Use the `useRef()` hook to create a `ref` for the `value`.
- Use the `useEffect()` hook to remember the latest `value`.

```jsx
const usePrevious = value => {
  const ref = React.useRef();
  React.useEffect(() => {
    ref.current = value;
  });
  return ref.current;
};
```

```jsx
const Counter = () => {
  const [value, setValue] = React.useState(0);
  const lastValue = usePrevious(value);

  return (
    <div>
      <p>
        Current: {value} - Previous: {lastValue}
      </p>
      <button onClick={() => setValue(value + 1)}>Increment</button>
    </div>
  );
};

ReactDOM.render(<Counter />, document.getElementById('root'));
```