Stacked on https://github.com/facebook/react/pull/30400 and https://github.com/facebook/react/pull/30369 Previously we were using fake evals to recreate a stack for console replaying and thrown errors. However, for owner stacks we just used the raw string that came from the server. This means that the format of the owner stack could include different formats. Like Spidermonkey format for the client components and V8 for the server components. This means that this stack can't be parsed natively by the browser like when printing them as error like in https://github.com/facebook/react/pull/30289. Additionally, since there's no source file registered with that name and no source mapping url, it can't be source mapped. Before: <img width="1329" alt="before-firefox" src="https://github.com/user-attachments/assets/cbe03f9c-96ac-48fb-b58f-f3a224a774f4"> Instead, we need to create a fake stack like we do for the other things. That way when it's printed as an Error it gets source mapped. It also means that the format is consistently in the native format of the current browser. After: <img width="753" alt="after-firefox" src="https://github.com/user-attachments/assets/b436f1f5-ca37-4203-b29f-df9828c9fad3"> So this is nice because you can just take the result from `captureOwnerStack()` and append it to an `Error` stack and print it natively. E.g. this is what React DevTools will do. If you want to parse and present it yourself though it's a bit awkward though. The `captureOwnerStack()` API now includes a bunch of `rsc://React/` URLs. These don't really have any direct connection to the source map. Only the browser knows this connection from the eval. You basically have to strip the prefix and then manually pass the remainder to your own `findSourceMapURL`. Another awkward part is that since Safari doesn't support eval sourceURL exposed into `error.stack` - it means that `captureOwnerStack()` get an empty location for server components since the fake eval doesn't work there. That's not a big deal since these stacks are already broken even for client modules for many because the `eval-source-map` strategy in Webpack doesn't work in Safari for this same reason. A lot of this refactoring is just clarifying that there's three kind of ReactComponentInfo fields: - `stack` - The raw stack as described on the original server. - `debugStack` - The Error object containing the stack as represented in the current client as fake evals. - `debugTask` - The same thing as `debugStack` but described in terms of a native `console.createTask`.
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.