What is the different ReactDOM.findDOMNode(this.refs.a) vs this.refs.a?

Question

If getting element object directly from this.refs then Why ReactDOM.findDOMNode?

var HelloMessage = React.createClass({
click:function(){
  console.log(ReactDOM.findDOMNode(this.refs.a))
  console.log(ReactDOM.findDOMNode(this.refs.b))
  console.log(this.refs.a)
  console.log(this.refs.b)
},
  render: function() {
    return <div><div onClick={this.click}>click</div>Hello {this.props.name}{this.props.no?<div ref="a">{this.props.no}</div>:<div ref="b"></div>}</div>;
  }
});

ReactDOM.render(<HelloMessage name="John" no={1}/>, mountNode);

Answer 1

From the usage perspective there is no difference between these.

ReactDOM.findDOMNode was a way of getting ref in the past. Currently it's deprecated and this.refs is how you should do it now.