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https://github.com/the-road-to-learn-react/use-state-with-callback

Custom hook to include a callback function for useState.
https://github.com/the-road-to-learn-react/use-state-with-callback

callback react react-hook react-hooks react-use-state-callback reactjs

Last synced: 8 months ago
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Custom hook to include a callback function for useState.

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README

          

# useStateWithCallback React Hook

[![Build Status](https://travis-ci.org/the-road-to-learn-react/use-state-with-callback.svg?branch=master)](https://travis-ci.org/the-road-to-learn-react/use-state-with-callback) [![Greenkeeper badge](https://badges.greenkeeper.io/the-road-to-learn-react/use-state-with-callback.svg)](https://greenkeeper.io/) ![NPM](https://img.shields.io/npm/l/use-state-with-callback.svg)

Custom hook to include a callback function for useState which was previously available for setState in class components. [Read more about it here.](https://www.robinwieruch.de/react-usestate-callback/)

## Installation

`npm install use-state-with-callback`

## Usage

**useStateWithCallback:**

```jsx
import * as React from 'react';

import useStateWithCallback from 'use-state-with-callback';

// Note: cannot be used on the server-side (e.g. Next.js)
// import { useStateWithCallbackInstant } from 'use-state-with-callback';

const App = () => {
const [count, setCount] = useStateWithCallback(0, currentCount => {
console.log('render, then callback.');
console.log('otherwise use useStateWithCallbackInstant()');

if (currentCount > 1) {
console.log('Threshold of over 1 reached.');
} else {
console.log('No threshold reached.');
}
});

// const [count, setCount] = useStateWithCallbackInstant(0, currentCount => {
// console.log('render with instant callback.');

// if (currentCount > 1) {
// console.log('Threshold of over 1 reached.');
// } else {
// console.log('No threshold reached.');
// }
// });

const handleClick = () => {
setCount(count + 1);
};

return (


{count}


Increase


);
};

export default App;
```

**useStateWithCallbackLazy:**

```jsx
import * as React from 'react';
import { useStateWithCallbackLazy } from 'use-state-with-callback';

const App = () => {
const [count, setCount] = useStateWithCallbackLazy(0);

const handleClick = () => {
setCount(count + 1, (currentCount) => {
if (currentCount > 1) {
console.log('Threshold of over 1 reached.');
} else {
console.log('No threshold reached.');
}
});
};

return (


{count}


Increase


);
};

export default App;
```

## Pitfalls

* When a state update is called with the current value and optimized away, the callback is never called.
* `useStateWithCallbackLazy` calls the callback with the scope that existed before update, while this.setState callback can access the updated this.state and `get something()` computed values. This can't be fixed, but it's a problem for people who expect a drop-in replacement.
* When `useStateWithCallbackLazy` state is updated several times with batching (e.g. in an event handler), only the last update calls the callback.

## Contribute

- `git clone git@github.com:the-road-to-learn-react/use-state-with-callback.git`
- `cd use-state-with-callback`
- `npm install`
- `npm run test`

### More

- [Publishing a Node Package to NPM](https://www.robinwieruch.de/publish-npm-package-node/)
- [Node.js Testing Setup](https://www.robinwieruch.de/node-js-testing-mocha-chai/)
- [React Testing Setup](https://www.robinwieruch.de/react-testing-tutorial/)