Optional
UNSAFE_Optional
UNSAFE_Called when the component may be receiving new props. React may call this even if props have not changed, so be sure to compare new and existing props if you only want to handle changes.
Calling Component#setState
generally does not trigger this method.
This method will not stop working in React 17.
Note: the presence of getSnapshotBeforeUpdate or getDerivedStateFromProps prevents this from being invoked.
16.3, use static getDerivedStateFromProps instead
Optional
UNSAFE_Called immediately before rendering when new props or state is received. Not called for the initial render.
Note: You cannot call Component#setState
here.
This method will not stop working in React 17.
Note: the presence of getSnapshotBeforeUpdate or getDerivedStateFromProps prevents this from being invoked.
16.3, use getSnapshotBeforeUpdate instead
Optional
componentCalled immediately before mounting occurs, and before Component#render
.
Avoid introducing any side-effects or subscriptions in this method.
Note: the presence of getSnapshotBeforeUpdate or getDerivedStateFromProps prevents this from being invoked.
16.3, use componentDidMount or the constructor instead; will stop working in React 17
Optional
componentCalled when the component may be receiving new props. React may call this even if props have not changed, so be sure to compare new and existing props if you only want to handle changes.
Calling Component#setState
generally does not trigger this method.
Note: the presence of getSnapshotBeforeUpdate or getDerivedStateFromProps prevents this from being invoked.
16.3, use static getDerivedStateFromProps instead; will stop working in React 17
Optional
componentCalled immediately before rendering when new props or state is received. Not called for the initial render.
Note: You cannot call Component#setState
here.
Note: the presence of getSnapshotBeforeUpdate or getDerivedStateFromProps prevents this from being invoked.
16.3, use getSnapshotBeforeUpdate instead; will stop working in React 17
Called immediately before mounting occurs, and before
Component#render
. Avoid introducing any side-effects or subscriptions in this method.This method will not stop working in React 17.
Note: the presence of getSnapshotBeforeUpdate or getDerivedStateFromProps prevents this from being invoked.
Deprecated
16.3, use componentDidMount or the constructor instead
See