React 16.3 lifecycle hook

componentWillUpdate.js

// before
componentWillUpdate(nextProps, nextState) {
  if (
    this.state.someStatefulValue !==
    nextState.someStatefulValue
  ) {
    nextProps.onChange(nextState.someStatefulValue);
  }
}

//after
componentDidUpdate(prevProps, prevState) {
  if (
    this.state.someStatefulValue !==
    prevState.someStatefulValue
  ) {
    this.props.onChange(this.state.someStatefulValue);
  }
}