mirror of
https://github.com/facebook/react.git
synced 2026-02-24 04:33:04 +00:00
5031ebf6be
* Accept promise as element type On the initial render, the element will suspend as if a promise were thrown from inside the body of the unresolved component. Siblings should continue rendering and if the parent is a Placeholder, the promise should be captured by that Placeholder. When the promise resolves, rendering resumes. If the resolved value has a `default` property, it is assumed to be the default export of an ES module, and we use that as the component type. If it does not have a `default` property, we use the resolved value itself. The resolved value is stored as an expando on the promise/thenable. * Use special types of work for lazy components Because reconciliation is a hot path, this adds ClassComponentLazy, FunctionalComponentLazy, and ForwardRefLazy as special types of work. The other types are not supported, but wouldn't be placed into a separate module regardless. * Resolve defaultProps for lazy types * Remove some calls to isContextProvider isContextProvider checks the fiber tag, but it's typically called after we've already refined the type of work. We should get rid of it. I removed some of them in the previous commit, and deleted a few more in this one. I left a few behind because the remaining ones would require additional refactoring that feels outside the scope of this PR. * Remove getLazyComponentTypeIfResolved * Return baseProps instead of null The caller compares the result to baseProps to see if anything changed. * Avoid redundant checks by inlining getFiberTagFromObjectType * Move tag resolution to ReactFiber module * Pass next props to update* functions We should do this with all types of work in the future. * Refine component type before pushing/popping context Removes unnecessary checks. * Replace all occurrences of _reactResult with helper * Move shared thenable logic to `shared` package * Check type of wrapper object before resolving to `default` export * Return resolved tag instead of reassigning
react-test-renderer
This package provides an experimental React renderer that can be used to render React components to pure JavaScript objects, without depending on the DOM or a native mobile environment.
Essentially, this package makes it easy to grab a snapshot of the "DOM tree" rendered by a React DOM or React Native component without using a browser or jsdom.
Documentation:
https://reactjs.org/docs/test-renderer.html
Usage:
const ReactTestRenderer = require('react-test-renderer');
const renderer = ReactTestRenderer.create(
<Link page="https://www.facebook.com/">Facebook</Link>
);
console.log(renderer.toJSON());
// { type: 'a',
// props: { href: 'https://www.facebook.com/' },
// children: [ 'Facebook' ] }
You can also use Jest's snapshot testing feature to automatically save a copy of the JSON tree to a file and check in your tests that it hasn't changed: https://facebook.github.io/jest/blog/2016/07/27/jest-14.html.