60368f34b2
This adds VirtualInstances to the tree. Each Fiber has a list of its parent Server Components in `_debugInfo`. The algorithm is that when we enter a set of fibers, we actually traverse level 0 of all the `_debugInfo` in each fiber. Then level 1 of each `_debugInfo` and so on. It would be simpler if `_debugInfo` only contained Server Component since then we could just look at the index in the array but it actually contains other data as well which leads to multiple passes but we don't expect it to have a lot of levels before hitting a reified fiber. Finally when we hit the end a traverse the fiber itself. This lets us match consecutive `ReactComponentInfo` that are all the same at the same level. This creates a single VirtualInstance for each sequence. This lets the same Server Component instance that's a parent to multiple children appear as a single Instance instead of one per Fiber. Since a Server Component's result can be rendered in more than one place there's not a 1:1 mapping though. If it is in different parents or if the sequence is interrupted, then it gets split into two different instances with the same `ReactComponentInfo` data. The real interesting case is what happens during updates because this algorithm means that a Fiber can become reparented during an update to end up in a different VirtualInstance. The ideal would maybe be that the frontend could deal with this reparenting but instead I basically just unmount the previous instance (and its children) and mount a new instance which leads to some interesting scenarios. This is inline with the strategy I was intending to pursue anyway where instances are reconciled against the previous children of the same parent instead of the `fiberToFiberInstance` map - which would let us get rid of that map. In that case the model is resilient to Fiber being in more than one place at a time. However this unmount/remount does mean that we can lose selection when this happens. We could maybe do something like using the tracked path like I did for component filters. Ideally it's a weird edge case though because you'd typically not have it. The main case that it happens now is for reorders of list of server components. In that case basically all the children move between server components while the server components themselves stay in place. We should really include the key in server components so that we can reconcile them using the key to handle reorders which would solve the common case anyway. I convert the name to the `Env(Name)` pattern which allows the Environment Name to be used as a badge. <img width="1105" alt="Screenshot 2024-08-13 at 9 55 29 PM" src="https://github.com/user-attachments/assets/323c20ba-b655-4ee8-84fa-8233f55d2999"> (Screenshot is with #30667. I haven't tried it with the alternative fix.) --------- Co-authored-by: Ruslan Lesiutin <[email protected]>
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.