Andrew Clark
3addf205bf
* Remove Task priority The concept of Task priority was originally added as a way to avoid reentrancy. Sync priority is for work that flushes synchronously, and Task is for work that flushes at the end of the event loop. But it turns out that in most cases, it's simpler to model Task and Sync as the same priority level. For example, it's never correct to flush Sync work from the update queue without flushing Task. Doing so can lead to infinite update loops. And using a separate priority level is not necessary to avoid reentrancy. We already track when work is being rendered, and exit before entering the render cycle again. That alone is sufficient. This commit removes Task priority from the codebase. Now we use the same level for both truly synchronous work and work that is deferred until the end of the event loop. This also enables us to remove DOM-specific legacy cases from the reconciler and lift them to the renderer. * Remove isUnbatched from FiberRoot Simpler to render unbatched roots immediately. * Use a cyclic linked list for root schedule Avoids the need for a separate `isScheduled` field.
React · 
React is a JavaScript library for building user interfaces.
- Declarative: React makes it painless to create interactive UIs. Design simple views for each state in your application, and React will efficiently update and render just the right components when your data changes. Declarative views make your code more predictable, simpler to understand, and easier to debug.
- Component-Based: Build encapsulated components that manage their own state, then compose them to make complex UIs. Since component logic is written in JavaScript instead of templates, you can easily pass rich data through your app and keep state out of the DOM.
- Learn Once, Write Anywhere: We don't make assumptions about the rest of your technology stack, so you can develop new features in React without rewriting existing code. React can also render on the server using Node and power mobile apps using React Native.
Learn how to use React in your own project.
Examples
We have several examples on the website. Here is the first one to get you started:
class HelloMessage extends React.Component {
render() {
return <div>Hello {this.props.name}</div>;
}
}
ReactDOM.render(
<HelloMessage name="John" />,
document.getElementById('container')
);
This example will render "Hello John" into a container on the page.
You'll notice that we used an HTML-like syntax; we call it JSX. JSX is not required to use React, but it makes code more readable, and writing it feels like writing HTML. We recommend using Babel with a React preset to convert JSX into native JavaScript for browsers to digest.
Installation
React is available as the react package on npm. It is also available on a CDN.
React is flexible and can be used in a variety of projects. You can create new apps with it, but you can also gradually introduce it into an existing codebase without doing a rewrite.
The recommended way to install React depends on your project. Here you can find short guides for the most common scenarios:
Contributing
The main purpose of this repository is to continue to evolve React core, making it faster and easier to use. Development of React happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving React.
Code of Conduct
Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please read the full text so that you can understand what actions will and will not be tolerated.
Contributing Guide
Read our contributing guide to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes to React.
Beginner Friendly Bugs
To help you get your feet wet and get you familiar with our contribution process, we have a list of beginner friendly bugs that contain bugs which are fairly easy to fix. This is a great place to get started.
License
React is MIT licensed.