react-dom

Breaking Changes

• There are several changes to the behavior of scheduling and lifecycle methods:
  • ReactDOM.render() and ReactDOM.unstable_renderIntoContainer() now return null if called from inside a lifecycle method.
    • To work around this, you can either use the new portal API or refs.
  • Minor changes to setState behavior:
    • Calling setState with null no longer triggers an update. This allows you to decide in an updater function if you want to re-render.
    • Calling setState directly in render always causes an update. This was not previously the case. Regardless, you should not be calling setState from render.
    • setState callback (second argument) now fires immediately after componentDidMount / componentDidUpdate instead of after all components have rendered.
  • When replacing <A /> with <B />, B.componentWillMount now always happens before A.componentWillUnmount. Previously, A.componentWillUnmount could fire first in some cases.
  • Previously, changing the ref to a component would always detach the ref before that component's render is called. Now, we change the ref later, when applying the changes to the DOM.
  • It is not safe to re-render into a container that was modified by something other than React. This worked previously in some cases but was never supported. We now emit a warning in this case. Instead you should clean up your component trees using ReactDOM.unmountComponentAtNode. See this example.
  • componentDidUpdate lifecycle no longer receives prevContext param. (@bvaughn in #8631)
  • Non-unique keys may now cause children to be duplicated and/or omitted. Using non-unique keys is not (and has never been) supported, but previously it was a hard error.
  • Shallow renderer no longer calls because DOM refs are not available. This also makes it consistent with (which does not get called in previous versions either).