Stacked on #30197. This is similar to #30182 and #21610 in Fizz. Track the current owner/stack/task on the task. This tracks it for attribution when serializing child properties. This lets us provide the right owner and createTask when we console.error from inside Flight itself. This also affects the way we print those logs on the client since we need the owner and stack. Now console.errors that originate on the server gets the right stack on the client: <img width="760" alt="Screenshot 2024-07-03 at 6 03 13 PM" src="https://github.com/facebook/react/assets/63648/913300f8-f364-4e66-a19d-362e8d776c64"> Unfortunately, because we don't track the stack we never pop it so it'll keep tracking for serializing sibling properties. We rely on "children" typically being the last property in the common case anyway. However, this can lead to wrong attribution in some cases where the invalid property is a next property (without a wrapping element) and there's a previous element that doesn't. E.g. `<ClientComponent title={<div />} invalid={nonSerializable} />` would use the div as the attribution instead of ClientComponent. I also wrap all of our own console.error, onError and onPostpone in the context of the parent component. It's annoying to have to remember to do this though. We could always wrap the whole rendering in such as context but it would add more overhead since this rarely actually happens. It might make sense to track the whole current task instead to lower the overhead. That's what we do in Fizz. We'd still have to remember to restore the debug task though. I realize now Fizz doesn't do that neither so the debug task isn't wrapping the console.errors that Fizz itself logs. There's something off about that Flight and Fizz implementations don't perfectly align.
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 Quick Start to get a taste of React.
- Add React to an Existing Project to use as little or as much React as you need.
- Create a New React App if you're looking for a powerful JavaScript toolchain.
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:
- Quick Start
- Tutorial
- Thinking in React
- Installation
- Describing the UI
- Adding Interactivity
- Managing State
- Advanced Guides
- API Reference
- Where to Get Support
- Contributing Guide
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.
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.