#Class: PureComponent<P = { }, S = { }, SS = any>

#Extends

• Component<P, S, SS>

#Type Parameters

#Constructors

#Constructor

new PureComponent<P = { }, S = { }, SS = any>(props: P): PureComponent<P, S, SS>

#Parameters

#Returns

PureComponent<P, S, SS>

#Inherited from

Component.constructor

#Constructor

new PureComponent<P = { }, S = { }, SS = any>(props: P, context: any): PureComponent<P, S, SS>

#Parameters

#Returns

PureComponent<P, S, SS>

#Inherited from

Component.constructor

#Properties

#context

context: unknown

If using React Context, re-declare this in your class to be the React.ContextType of your static contextType. Should be used with type annotation or static contextType.

#Example

static contextType = MyContext
// For TS pre-3.7:
context!: React.ContextType<typeof MyContext>
// For TS 3.7 and above:
declare context: React.ContextType<typeof MyContext>

#See

React Docs

#Inherited from

Component.context

#props

readonly props: Readonly<P>

#Inherited from

Component.props

#state

state: Readonly<S>

#Inherited from

Component.state

#contextType?

static optional contextType?: Context<any>

If set, this.context will be set at runtime to the current value of the given Context.

#Example

type MyContext = number
const Ctx = React.createContext<MyContext>(0)

class Foo extends React.Component {
  static contextType = Ctx
  context!: React.ContextType<typeof Ctx>
  render () {
    return <>My context's value: {this.context}</>;
  }
}

#See

https://react.dev/reference/react/Component#static-contexttype

#Inherited from

Component.contextType

#propTypes?

static optional propTypes?: any

Ignored by React.

#Deprecated

Only kept in types for backwards compatibility. Will be removed in a future major release.

#Inherited from

Component.propTypes

#Methods

#componentDidCatch()?

optional componentDidCatch(error: Error, errorInfo: ErrorInfo): void

Catches exceptions generated in descendant components. Unhandled exceptions will cause the entire component tree to unmount.

#Parameters

#Returns

void

#Inherited from

Component.componentDidCatch

#componentDidMount()?

optional componentDidMount(): void

Called immediately after a component is mounted. Setting state here will trigger re-rendering.

#Returns

void

#Inherited from

Component.componentDidMount

#componentDidUpdate()?

optional componentDidUpdate(prevProps: Readonly<P>, prevState: Readonly<S>, snapshot?: SS): void

Called immediately after updating occurs. Not called for the initial render.

The snapshot is only present if getSnapshotBeforeUpdate is present and returns non-null.

#Parameters

#Returns

void

#Inherited from

Component.componentDidUpdate

#componentWillMount()?

optional componentWillMount(): void

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.

#Returns

void

#Deprecated

16.3, use componentDidMount or the constructor instead; will stop working in React 17

#See

• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#initializing-state
• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#gradual-migration-path

#Inherited from

Component.componentWillMount

#componentWillReceiveProps()?

optional componentWillReceiveProps(nextProps: Readonly<P>, nextContext: any): void

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.

#Parameters

#Returns

void

#Deprecated

16.3, use static getDerivedStateFromProps instead; will stop working in React 17

#See

• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#updating-state-based-on-props
• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#gradual-migration-path

#Inherited from

Component.componentWillReceiveProps

#componentWillUnmount()?

optional componentWillUnmount(): void

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.

#Returns

void

#Inherited from

Component.componentWillUnmount

#componentWillUpdate()?

optional componentWillUpdate(nextProps: Readonly<P>, nextState: Readonly<S>, nextContext: any): void

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.

#Parameters

#Returns

void

#Deprecated

16.3, use getSnapshotBeforeUpdate instead; will stop working in React 17

#See

• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#reading-dom-properties-before-an-update
• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#gradual-migration-path

#Inherited from

Component.componentWillUpdate

#forceUpdate()

forceUpdate(callback?: () => void): void

#Parameters

#Returns

void

#Inherited from

Component.forceUpdate

#getSnapshotBeforeUpdate()?

optional getSnapshotBeforeUpdate(prevProps: Readonly<P>, prevState: Readonly<S>): SS | null

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 this method prevents any of the deprecated lifecycle events from running.

#Parameters

#Returns

SS | null

#Inherited from

Component.getSnapshotBeforeUpdate

#render()

render(): ReactNode

#Returns

ReactNode

#Inherited from

Component.render

#setState()

setState<K extends string | number | symbol>(state: S | ((prevState: Readonly<S>, props: Readonly<P>) => S | Pick<S, K> | null) | Pick<S, K> | null, callback?: () => void): void

#Type Parameters

#Parameters

#Returns

void

#Inherited from

Component.setState

#shouldComponentUpdate()?

optional shouldComponentUpdate(nextProps: Readonly<P>, nextState: Readonly<S>, nextContext: any): boolean

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.

#Parameters

#Returns

boolean

#Inherited from

Component.shouldComponentUpdate

#UNSAFE_componentWillMount()?

optional UNSAFE_componentWillMount(): void

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.

#Returns

void

#Deprecated

16.3, use componentDidMount or the constructor instead

#See

• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#initializing-state
• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#gradual-migration-path

#Inherited from

Component.UNSAFE_componentWillMount

#UNSAFE_componentWillReceiveProps()?

optional UNSAFE_componentWillReceiveProps(nextProps: Readonly<P>, nextContext: any): void

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.

#Parameters

#Returns

void

#Deprecated

16.3, use static getDerivedStateFromProps instead

#See

• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#updating-state-based-on-props
• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#gradual-migration-path

#Inherited from

Component.UNSAFE_componentWillReceiveProps

#UNSAFE_componentWillUpdate()?

optional UNSAFE_componentWillUpdate(nextProps: Readonly<P>, nextState: Readonly<S>, nextContext: any): void

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.

#Parameters

#Returns

void

#Deprecated

16.3, use getSnapshotBeforeUpdate instead

#See

• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#reading-dom-properties-before-an-update
• https://legacy.reactjs.org/blog/2018/03/27/update-on-async-rendering.html#gradual-migration-path

#Inherited from

Component.UNSAFE_componentWillUpdate