Andrew Clark
4d5cb64aa2
* Rewrite ReactFiberScheduler Adds a new implementation of ReactFiberScheduler behind a feature flag. We will maintain both implementations in parallel until the new one is proven stable enough to replace the old one. The main difference between the implementations is that the new one is integrated with the Scheduler package's priority levels. * Conditionally add fields to FiberRoot Some fields only used by the old scheduler, and some by the new. * Add separate build that enables new scheduler * Re-enable skipped test If synchronous updates are scheduled by a passive effect, that work should be flushed synchronously, even if flushPassiveEffects is called inside batchedUpdates. * Passive effects have same priority as render * Revert ability to cancel the current callback React doesn't need this anyway because it never schedules callbacks if it's already rendering. * Revert change to FiberDebugPerf Turns out this isn't neccessary. * Fix ReactFiberScheduler dead code elimination Should initialize to nothing, then assign the exports conditionally, instead of initializing to the old exports and then reassigning to the new ones. * Don't yield before commit during sync error retry * Call Scheduler.flushAll unconditionally in tests Instead of wrapping in enableNewScheduler flag.
react-reconciler
This is an experimental package for creating custom React renderers.
Its API is not as stable as that of React, React Native, or React DOM, and does not follow the common versioning scheme.
Use it at your own risk.
API
const Reconciler = require('react-reconciler');
const HostConfig = {
// You'll need to implement some methods here.
// See below for more information and examples.
};
const MyRenderer = Reconciler(HostConfig);
const RendererPublicAPI = {
render(element, container, callback) {
// Call MyRenderer.updateContainer() to schedule changes on the roots.
// See ReactDOM, React Native, or React ART for practical examples.
}
};
module.exports = RendererPublicAPI;
Practical Examples
A "host config" is an object that you need to provide, and that describes how to make something happen in the "host" environment (e.g. DOM, canvas, console, or whatever your rendering target is). It looks like this:
const HostConfig = {
createInstance(type, props) {
// e.g. DOM renderer returns a DOM node
},
// ...
supportsMutation: true, // it works by mutating nodes
appendChild(parent, child) {
// e.g. DOM renderer would call .appendChild() here
},
// ...
};
For an introduction to writing a very simple custom renderer, check out this article series:
The full list of supported methods can be found here. For their signatures, we recommend looking at specific examples below.
The React repository includes several renderers. Each of them has its own host config.
The examples in the React repository are declared a bit differently than a third-party renderer would be. In particular, the HostConfig object mentioned above is never explicitly declared, and instead is a module in our code. However, its exports correspond directly to properties on a HostConfig object you'd need to declare in your code:
- React ART and its host config
- React DOM and its host config
- React Native and its host config
If these links break please file an issue and we’ll fix them. They intentionally link to the latest versions since the API is still evolving. If you have more questions please file an issue and we’ll try to help!