React: Getting a component from a DOM element

dom2comp.js

let searchRoot = ReactDom.render(React.createElement(Main), document.getElementById('main'));
try {
  var getComponent = (comp) => comp._renderedComponent ? getComponent(comp._renderedComponent) : comp;

  var getComponentById = (id)=> {
    var comp = searchRoot._reactInternalInstance;
    var path = id.substr(1).split('.').map(a=> '.' + a);
    if (comp._rootNodeID !== path.shift()) throw 'Unknown root';
    while (path.length > 0) {
      comp = getComponent(comp)._renderedChildren[path.shift()];
    }
    return comp._instance;
  };

  window.$r = (node)=> getComponentById(node.getAttribute('data-reactid'))
} catch (e) {
  console.info(e);
}