Andrew Clark
1022ee0ec1
* Failing test: DevTools hook freezes timeline The DevTools hook calls `requestCurrentTime` after the commit phase has ended, which has the accidnental consequence of freezing the start time for subsequent updates. If enough time goes by, the next update will instantly expire. I'll push a fix in the next commit. * Read current time without marking event start time `requestCurrentTime` is only meant to be used for updates, because subsequent calls within the same event will receive the same time. Messing this up has bad consequences. I renamed it to `requestCurrentTimeForUpdate` and created a new function that returns the current time without the batching heuristic, called `getCurrentTime`. Swapping `requestCurrentTime` for `getCurrentTime` in the DevTools hook fixes the regression test added in the previous commit.
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!