112168f31b
* Lint rule for unminified errors Add a lint rule that fails if an invariant message is not part of the error code map. The goal is to be more disciplined about adding and modifiying production error codes. Error codes should be consistent across releases even if their wording changes, for continuity in logs. Currently, error codes are added to the error code map via an automated script that runs right before release. The problem with this approach is that if someone modifies an error message in the source, but neglects to modify the corresponding message in the error code map, then the message will be assigned a new error code, instead of reusing the existing one. Because the error extraction script only runs before a release, people rarely modify the error code map in practice. By moving the extraction step to the PR stage, it forces the author to consider whether the message should be assigned a new error code. It also allows the reviewer to review the changes. The trade off is that it requires more effort and context to land new error messages, or to modify existing ones, particular for new contributors who are not familiar with our processes. Since we already expect users to lint their code, I would argue the additional burden is marginal. Even if they forget to run the lint command locally, they will get quick feedback from the CI lint job, which typically finishes within 2-3 minutes. * Add unreleased error messages to map
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:
function HelloMessage({ name }) {
return <div>Hello {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.