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.
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.
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.
Catches exceptions generated in descendant components. Unhandled exceptions will cause the entire component tree to unmount.
Called immediately after a component is mounted. Setting state here will trigger re-rendering.
Called immediately after updating occurs. Not called for the initial render.
The snapshot is only present if getSnapshotBeforeUpdate is present and returns non-null.
Called 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.
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.
Note: the presence of getSnapshotBeforeUpdate or getDerivedStateFromProps prevents this from being invoked.
Called immediately before a component is destroyed. Perform any necessary cleanup in this method, such as
cancelled network requests, or cleaning up any DOM elements created in componentDidMount.
Called 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.
Runs 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 getSnapshotBeforeUpdate prevents any of the deprecated lifecycle events from running.
Called 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, Component#render, componentWillUpdate
and componentDidUpdate will not be called.
Generated using TypeDoc
Props: CallableAsyncProps extends Omit<AsyncProps, 'children' | 'params'>
A render-prop component that injects an
AsyncLifecyclefor anyAsyncOperationinto the component tree. Identical to Async, except that instead of acceptingparamsas a prop, it passescall(...params: Params)to its children. As such,CallableAsyncgives thechildrencontrol over when the operation is executed - typically as a result of a user interaction. This can be used for user-initiated asynchronous calls, such as saving a form.The following example invokes
savewhen the button is clicked:// type save = (entity: Entity) => Promise <CallableAsync operation={save}> {(state, call) => <div> { // If the Promise is rejected, render the error. state.error ? <span className="error">{state.error}</span> // If the Promise resolves, render a success message. : state.status === 'complete' ? <span className="success">Entity saved successfully.</span> // If the operation is active, render a loading indicator. : state.status === 'active' && <span className="loading" /> } <button onClick={() => save(entity)}> Save </button> </div>} </CallableAsync>The implementation of
CallableAsyncis trivial. It is a stateful wrapper aroundAsyncthat callssetState(params)whencall(params)is invoked. More complex use cases that are not met byAsyncorCallableAsynccan be achieved using a similar strategy.