React-Lifecycle-Cheatsheet/README.md

React-Lifecycle-Cheatsheet

Short reference of React.Component lifecycle methods so I don't have to scroll through the huge text on the official documentation

Mounting

constructor ()

/**
 * Create state and call super
 *
 * @param {object} props
 */
constructor (props) {
	super(props);
	this.state = {
		foo: 'bar'
	}
}

static getDerivedStateFromProps ()

/**
 * Props have changed, return the updated state
 *
 * @param {object} nextProps - Props for the next render
 * @param {object} prevState - State from previous render
 * @return {object | null} - The change to the state 
 */
static getDerivedStateFromProps (nextProps, prevState) {
	// Nothing to update
	return null;
	
	// Set new state
	return {
		foo: 'foobar'
	};
} 

componentDidMount ()

/**
 * Component mounted, will render soon
 */
componentDidMount () {
	// Network calls, state changes, 
	// anything is fair game here
}

Updating

shouldComponentUpdate ()

/**
 * Hook to control re-render
 *
 * @param {object} nextProps
 * @param {object} nextState
 * @return {boolean} - Whether to render this cycle
 */
shouldComponentUpdate (nextProps, nextState) {
	// Default in React.Component
	return true;
	
	// React.PureComponent implements this method
	// with a shallow compare of props and state
}

render ()

/**
 * Render returned components
 *
 * @return {React Element | string | number | Portal | null | boolean}
 */
render () {
	return <div />;
}

getSnapshotBeforeUpdate ()

getSnapshotBeforeUpdate (prevProps, prevState) {
}

componentDidUpdate ()

componentDidUpdate (prevProps, prevState, snapshot = undefined) {
}

Unmounting

componentWillUnmount ()

componentWillUnMount () {
	// Cleanup whatever you need to before the
	// component unmounts
}

---

Deprecated

UNSAFE_componentWillMount ()

UNSAFE_componentWillReceiveProps ()

UNSAFE_componentWillUpdate ()