React example is incorrect

[rus-yurchenko]

Hi there,
I found an issue with a React ref example. Inside a render() method you suggest to

pass your ref with the reference to the targetElement

But if we do so, we don't assign actually this.targetRef to the component and will always get a {current: null} from react ref.
Changed this.targetElement with this.targetRef worked for me.

render() {   
    return (
      // change this.targetElement with this.targetRef to actually access a react ref
      {/*<SomeOtherComponent ref={this.targetElement}>*/}
      <SomeOtherComponent ref={this.targetRef}>
        some JSX to go here
      </SomeOtherComponent> 
    );
  }

Please update the README example.