Flarnie Marchan
a9abd27e4f
* Support using id to cancel scheduled callback **what is the change?:** see title **why make this change?:** Once we support multiple callbacks you will need to use the id to specify which callback you mean. **test plan:** Added a test, ran all tests, lint, etc. * ran prettier * fix lint * Use object for storing callback info in scheduler * Wrap initial test in a describe block * Support multiple callbacks in `ReactScheduler` **what is the change?:** We keep a queue of callbacks instead of just one at a time, and call them in order first by their timeoutTime and then by the order which they were scheduled in. **why make this change?:** We plan on using this module to coordinate JS outside of React, so we will need to schedule more than one callback at a time. **test plan:** Added a boatload of shiny new tests. :) Plus ran all the old ones. NOTE: The tests do not yet cover the vital logic of callbacks timing out, and later commits will add the missing test coverage. * Heuristic to avoid looking for timed out callbacks when none timed out **what is the change?:** Tracks the current soonest timeOut time for all scheduled callbacks. **why make this change?:** We were checking every scheduled callback to see if it timed out on every tick. It's more efficient to skip that O(n) check if we know that none have timed out. **test plan:** Ran existing tests. Will write new tests to cover timeout behavior in more detail soon. * Put multiple callback support under a disabled feature flag **what is the change?:** See title **why make this change?:** We don't have error handling in place yet, so should maintain the old behavior until that is in place. But want to get this far to continue making incremental changes. **test plan:** Updated and ran tests. * Hide support for multiple callbacks under a feature flag **what is the change?:** see title **why make this change?:** We haven't added error handling yet, so should not expose this feature. **test plan:** Ran all tests, temporarily split out the tests for multiple callbacks into separate file. Will recombine once we remove the flag. * Fix nits from code review See comments on https://github.com/facebook/react/pull/12743 * update checklist in comments * Remove nested loop which calls additional timed out callbacks **what is the change?:** We used to re-run any callbacks which time out whilst other callbacks are running, but now we will only check once for timed out callbacks then then run them. **why make this change?:** To simplify the code and the behavior of this module. **test plan:** Ran all existing tests. * Remove feature flag **what is the change?:** see title **why make this change?:** Because only React is using this, and it sounds like async. rendering won't hit any different behavior due to these changes. **test plan:** Existing tests pass, and this allowed us to recombine all tests to run in both 'test' and 'test-build' modes. * remove outdated file * fix typo
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.