Brian Vaughn
97e2911508
* Added unsafe_* lifecycles and deprecation warnings If the old lifecycle hooks (componentWillMount, componentWillUpdate, componentWillReceiveProps) are detected, these methods will be called and a deprecation warning will be logged. (In other words, we do not check for both the presence of the old and new lifecycles.) This commit is expected to fail tests. * Ran lifecycle hook codemod over project This should handle the bulk of the updates. I will manually update TypeScript and CoffeeScript tests with another commit. The actual command run with this commit was: jscodeshift --parser=flow -t ../react-codemod/transforms/rename-unsafe-lifecycles.js ./packages/**/src/**/*.js * Manually migrated CoffeeScript and TypeScript tests * Added inline note to createReactClassIntegration-test Explaining why lifecycles hooks have not been renamed in this test. * Udated NativeMethodsMixin with new lifecycle hooks * Added static getDerivedStateFromProps to ReactPartialRenderer Also added a new set of tests focused on server side lifecycle hooks. * Added getDerivedStateFromProps to shallow renderer Also added warnings for several cases involving getDerivedStateFromProps() as well as the deprecated lifecycles. Also added tests for the above. * Dedupe and DEV-only deprecation warning in server renderer * Renamed unsafe_* prefix to UNSAFE_* to be more noticeable * Added getDerivedStateFromProps to ReactFiberClassComponent Also updated class component and lifecyle tests to cover the added functionality. * Warn about UNSAFE_componentWillRecieveProps misspelling * Added tests to createReactClassIntegration for new lifecycles * Added warning for stateless functional components with gDSFP * Added createReactClass test for static gDSFP * Moved lifecycle deprecation warnings behind (disabled) feature flag Updated tests accordingly, by temporarily splitting tests that were specific to this feature-flag into their own, internal tests. This was the only way I knew of to interact with the feature flag without breaking our build/dist tests. * Tidying up * Tweaked warning message wording slightly Replaced 'You may may have returned undefined.' with 'You may have returned undefined.' * Replaced truthy partialState checks with != null * Call getDerivedStateFromProps via .call(null) to prevent type access * Move shallow-renderer didWarn* maps off the instance * Only call getDerivedStateFromProps if props instance has changed * Avoid creating new state object if not necessary * Inject state as a param to callGetDerivedStateFromProps This value will be either workInProgress.memoizedState (for updates) or instance.state (for initialization). * Explicitly warn about uninitialized state before calling getDerivedStateFromProps. And added some new tests for this change. Also: * Improved a couple of falsy null/undefined checks to more explicitly check for null or undefined. * Made some small tweaks to ReactFiberClassComponent WRT when and how it reads instance.state and sets to null. * Improved wording for deprecation lifecycle warnings * Fix state-regression for module-pattern components Also add support for new static getDerivedStateFromProps method
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.
Documentation
You can find the React documentation on the website.
It 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="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.
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.