Sebastian Markbåge
f172fa7461
Now that we no longer support Server Context, we can now deduplicate objects. It's not completely safe for useId but only in the same way as it's not safe if you reuse elements on the client, so it's not a new issue. This also solves cyclic object references. The issue is that we prefer to inline objects into a plain JSON format when an object is not going to get reused. In this case the object doesn't have an id. We could potentially serialize a reference to an existing model + a path to it but it bloats the format and complicates the client. In a smarter flush phase like we have in Fizz we could choose to inline or outline depending on what we've discovered so far before a flush. We can't do that here since we use native stringify. However, even in that solution you might not know that you're going to discover the same object later so it's not perfect deduping anyway. Instead, I use a heuristic where I mark previously seen objects and if I ever see that object again, then I'll outline it. The idea is that most objects are just going to be emitted once and if it's more than once it's fairly likely you have a shared reference to it somewhere and it might be more than two. The third object gets deduplicated (or "detriplicated"). It's not a perfect heuristic because when we write the second object we will have already visited all the nested objects inside of it, which causes us to outline every nested object too even those weren't reference more than by that parent. Not sure how to solve for that. If we for some other reason outline an object such as if it suspends, then it's truly deduplicated since it already has an id.
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 the 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 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:
import { createRoot } from 'react-dom/client';
function HelloMessage({ name }) {
return <div>Hello {name}</div>;
}
const root = createRoot(document.getElementById('container'));
root.render(<HelloMessage name="Taylor" />);
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 evolving 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 that have a relatively limited scope. This is a great place to get started.
License
React is MIT licensed.