React: How to access refs in this.props.children

Question

I want to call a function of a child component.
Is there a possibility to get refs from this.props.children in React.

var ComponentSection = React.createClass({

    componentDidMount: function() {
      // How to access refs in this.props.children ?
      this.refs.inner.refs.specificPanel.resize();
    },

    render: function () {
        return (
          <div className="component-section" ref="inner">
            {this.props.children}
          </div>
        );
    }
});

var Panel = React.createClass({

    resize: function() {
        console.log('Panel resizing');
    },

    render: function () {
        return (
          <div className="Panel">
            Lorem   ipsum dolor sit amet 
          </div>
        );
    }
});

var MainComponent = React.createClass({
    render: function () {
        return (
           <ComponentSection>
            <Panel ref="specificPanel"></Panel>
           </ComponentSection>
        );
    }
});

ReactDOM.render(
  <MainComponent></MainComponent>,
  document.getElementById('container')
);

I made a little demo: https://jsfiddle.net/69z2wepo/26929/

Thanks in advance

Answer 1

Ref in React is a relationship between a component and its owner while what you want is a relationship between an element and its parent. A parent-child relationship is opaque, the parent only receives the child elements on render and never gets access to the resolved components.

In your case, the ref="specificPanel" establishes a link from the MainComponent to the Panel. If you want to call methods of Panel from ComponentSection, it should own the Panels instead of receiving them as children.

You could always get creative with React.Children.map and React.createElement (cloning the elements by hand and thus stealing them from the original owner), but this introduces some serious potential pitfalls. A better approach would likely be re-thinking the ownership structure of your component tree.