Andrew Clark
5031ebf6be
* Accept promise as element type On the initial render, the element will suspend as if a promise were thrown from inside the body of the unresolved component. Siblings should continue rendering and if the parent is a Placeholder, the promise should be captured by that Placeholder. When the promise resolves, rendering resumes. If the resolved value has a `default` property, it is assumed to be the default export of an ES module, and we use that as the component type. If it does not have a `default` property, we use the resolved value itself. The resolved value is stored as an expando on the promise/thenable. * Use special types of work for lazy components Because reconciliation is a hot path, this adds ClassComponentLazy, FunctionalComponentLazy, and ForwardRefLazy as special types of work. The other types are not supported, but wouldn't be placed into a separate module regardless. * Resolve defaultProps for lazy types * Remove some calls to isContextProvider isContextProvider checks the fiber tag, but it's typically called after we've already refined the type of work. We should get rid of it. I removed some of them in the previous commit, and deleted a few more in this one. I left a few behind because the remaining ones would require additional refactoring that feels outside the scope of this PR. * Remove getLazyComponentTypeIfResolved * Return baseProps instead of null The caller compares the result to baseProps to see if anything changed. * Avoid redundant checks by inlining getFiberTagFromObjectType * Move tag resolution to ReactFiber module * Pass next props to update* functions We should do this with all types of work in the future. * Refine component type before pushing/popping context Removes unnecessary checks. * Replace all occurrences of _reactResult with helper * Move shared thenable logic to `shared` package * Check type of wrapper object before resolving to `default` export * Return resolved tag instead of reassigning
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.
Installation
React has been designed for gradual adoption from the start, and you can use as little or as much React as you need:
- Use Online Playgrounds to get a taste of React.
- Add React to a Website as a
<script>tag in one minute. - Create a New React App if you're looking for a powerful JavaScript toolchain.
You can use React as a <script> tag from a CDN, or as a react package on npm.
Documentation
You can find the React documentation on the website.
Check out the Getting Started page for a quick overview.
The documentation is divided into several sections:
You can improve it by sending pull requests to this repository.
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="Taylor" />,
document.getElementById('container')
);
This example will render "Hello Taylor" 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. If you're using React as a <script> tag, read this section on integrating JSX; otherwise, the recommended JavaScript toolchains handle it automatically.
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.
Good First Issues
To help you get your feet wet and get you familiar with our contribution process, we have a list of good first issues that contain bugs which have a relatively limited scope. This is a great place to get started.
License
React is MIT licensed.