Andrew Clark
c896cf9617
* Do not fix return pointers during commit phase In the commit phase, we should be able to assume that the `return` pointers in the just-completed tree are consistent. The render phase should be responsible for ensuring these are always correct. I've removed the `return` pointer assignments from the render phase traversal logic. This isn't all of them, only the ones added recently during the effects refactor. The other ones have been around longer so I'll leave those for a later clean up. This breaks a few SuspenseList tests; I'll fix in the next commit. * Set return pointer when reusing current tree We always set the return pointer on freshly cloned, work-in-progress fibers. However, we were neglecting to set them on trees that are reused from current. I fixed this in the same path of the complete phase where we reset the fiber flags. This is a code smell because it assumes the commit phase is never concurrent with the render phase. Our eventual goal is to make fibers a lock free data structure. Will address further during refactor to alternate model.
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!