Flarnie Marchan
413c7b548a
* Downgrade deprecation warnings from errors to warnings (#9650) * Downgrade deprecation warnings from errors to warnings **what is the change?:** Swapping out `warning` module for a fork that uses `console.warn`. It looks like we were using the `warning` module for deprecation notices, *but* there is also a 'deprecated' module designed specifically for deprecation notices. However, we could not find any place that it was currently used. Since React's build process is not 100% clear to me, I assume it could still be used somewhere by something and just updated it along with other deprecation notices. We might consider a follow-up diff that does some clean up here; - remove 'deprecated' module if it's unused, OR - use 'deprecated' module for all our current deprecation warnings **why make this change?:** - We have had complaints about noisy warnings, in particular after introducing new deprecations - They potentially cause CI failures - Deprecations are not really time-sensitive, can ship without breaking your app, etc. For more context - https://github.com/facebook/react/issues/9395 **test plan:** `npm run test` and unit tests for the new modules and manual testing (WIP) **issue:** https://github.com/facebook/react/issues/9395 * Add 'lowPriorityWarning' to ReactExternals **what is the change?:** We won't bundle 'lowPriorityWarning' with the rest of React when building for Facebook. NOTE: A parallel commit will introduce an internal implementation of 'lowPriorityWarning' in Facebook's codebase, to compensate. Will post a comment with the diff number once that is up. **why make this change?:** So that the sync between github and Facebook can go more smoothly! **test plan:** We will see when I run the sync! But this is a reasonable first step imo. **issue:** https://github.com/facebook/react/issues/9398 * Tweaks to get tests passing after cherry-picking PR#9650 **what is the change?:** - adds 'lowPriorityWarning' for deprecation of '__spread' and 'createMixin' - tweaks test to check for 'warn' and not 'error' **why make this change?:** Both these issues were introduced by merge conflict resolution when cherry-picking this change from master onto 15.6. **test plan:** `yarn test` **issue:** * Fix mis-written 'require' for 'warning' module **what is the change?:** Fixes 'warning' to be required from 'warning' **why make this change?:** It was causing the browserify build to crash, because we don't expect to have a path to 'warning'. **test plan:** CI
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. If you're interested in helping with that, check out our contribution guide.
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.
Good First Bug
To help you get your feet wet and get you familiar with our contribution process, we have a list of good first bugs that contain bugs which are fairly easy to fix. This is a great place to get started.
License
React is BSD licensed. We also provide an additional patent grant.
React documentation is Creative Commons licensed.
Examples provided in this repository and in the documentation are separately licensed.
Troubleshooting
See the Troubleshooting Guide