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 setState generally does not trigger this method.
This method will not stop working in React 17.
Note: the presence of getSnapshotBeforeUpdate or StaticLifecycle.getDerivedStateFromProps getDerivedStateFromProps prevents this from being invoked.
16.3, use static StaticLifecycle.getDerivedStateFromProps 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 setState here.
This method will not stop working in React 17.
Note: the presence of getSnapshotBeforeUpdate or StaticLifecycle.getDerivedStateFromProps getDerivedStateFromProps prevents this from being invoked.
16.3, use getSnapshotBeforeUpdate instead
Optional componentOptional componentOptional componentCalled immediately after updating occurs. Not called for the initial render.
The snapshot is only present if getSnapshotBeforeUpdate is present and returns non-null.
Optional componentCalled immediately before mounting occurs, and before render. Avoid introducing any side-effects or subscriptions in this method.
Note: the presence of getSnapshotBeforeUpdate or StaticLifecycle.getDerivedStateFromProps 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 setState generally does not trigger this method.
Note: the presence of getSnapshotBeforeUpdate or StaticLifecycle.getDerivedStateFromProps getDerivedStateFromProps prevents this from being invoked.
16.3, use static StaticLifecycle.getDerivedStateFromProps getDerivedStateFromProps instead; will stop working in React 17
Optional componentOptional componentCalled immediately before rendering when new props or state is received. Not called for the initial render.
Note: You cannot call setState here.
Note: the presence of getSnapshotBeforeUpdate or StaticLifecycle.getDerivedStateFromProps getDerivedStateFromProps prevents this from being invoked.
16.3, use getSnapshotBeforeUpdate instead; will stop working in React 17
Optional getRuns before React applies the result of render to the document, and returns an object to be given to componentDidUpdate. Useful for saving things such as scroll position before render causes changes to it.
Note: the presence of this method prevents any of the deprecated lifecycle events from running.
Optional shouldCalled to determine whether the change in props and state should trigger a re-render.
Component always returns true.
PureComponent implements a shallow comparison on props and state and returns true if any
props or states have changed.
If false is returned, render, componentWillUpdate
and componentDidUpdate will not be called.
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Called immediately before mounting occurs, and before 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 StaticLifecycle.getDerivedStateFromProps getDerivedStateFromProps prevents this from being invoked.
Deprecated
16.3, use componentDidMount or the constructor instead
See