monicao/react.md

## react.md

      
    Raw
  

              react.md
            
          
    React Component Lifecycle

getInitialState
getDefaultProps
componentWillMount
componentDidMount
shouldComponentUpdate (Update only)
componentWillUpdate (Update only)
componentWillReceiveProps (Update only)
render
componentDidUpdate (Update only)
componentWillUnmount/constructor
componentDidUnmount

TIPS

Keep state immutable
Use React.Children to work with this.props.children https://facebook.github.io/react/docs/top-level-api.html#react.children
Behaviour duplication in components can be refactored with mixins: https://facebook.github.io/react/docs/reusable-components.html#mixins
BUT prefer higher order components to mixins https://medium.com/@dan_abramov/mixins-are-dead-long-live-higher-order-components-94a0d2f9e750

getDefaultProps

The result of getDefaultProps() will be cached and used to ensure that this.props.value will have a value if it was not specified by the parent component.
componentWillMount()

Triggered before render().
componentDidMount

Called after render. Can access refs.
The componentDidMount() method of child components is invoked before that of parent components.
This is the place to call external libraries, use setTimeout, make ajax requests
shouldComponentUpdate(nextProps, nextState) - Update only

called when there are new props or state changes. return false to prevent a render. good for performance.
componentWillReceiveProps(nextProps)  - Update only

Called before render when props change. Access to old props.
It is not triggered after the component is mounted.
componentWillUpdate(nextProps, nextState)

Invoked immediately before rendering when new props or state are being received.
Not called for the initial render.
Cannot use setState in this method. Use componentWillReceiveProps instead.
Use this as an opportunity to perform preparation before an update occurs.
render

Triggered when the state changes.
componentDidUpdate(prevState, prevProps) - Update only

Access to prevState, prevProps
Use this as an opportunity to operate on the DOM when the component has been updated.
componentWillUnmount

Clean up event bindings, etc.