index.js
function updater(prevState) {
    var state = this.constructor.getDerivedStateFromProps(nextProps, prevState);
    return state !== null && state !== undefined ? state : null;
  }
function updater(prevState) {
    var state = this.constructor.getDerivedStateFromProps(nextProps, prevState);
    return state !== null && state !== undefined ? state : null;
  }
function updater ( prevState ) { var state = this . constructor . getDerivedStateFromProps ( nextProps , prevState ) ; return state !== null && state !== undefined ? state : null ; }
Call this.constructor.gDSFP to support sub-classes. Use the setState() updater to ensure state isn't stale in certain edge cases.
Call this . constructor . gDSFP to support sub - classes . Use the setState () updater to ensure state isn t stale in certain edge cases .