The code

``` javascript
class Comp extends React.Component {
  componentWillMount() {
    setTimeout(() => {
      this.setState({});
    });
  }

  render() {
    return <div onClick={() => {}} />;
  }
}

ReactDOMServer.renderToString(<Comp />);
```

produces errors:

> Warning: React can't find the root component node for data-reactid value `.0`. If you're seeing this message, it probably means that you've loaded two copies of React on the page. At this time, only a single copy of React can be loaded at a time.
> 
> Uncaught TypeError: Cannot read property 'firstChild' of undefined

But if I remove `onClick` handler the errors go away...

See demo: http://codepen.io/dened/pen/YyByYr

close: ReactInputSelection.restoreSelection,
};
/**
 * Suppresses events (blur/focus) that could be inadvertently dispatched due to
 * high level DOM manipulations (like temporarily removing a text input from the
 * DOM).
 */
var EVENT_SUPPRESSION = {
  /**
   * @return {boolean} The enabled status of `ReactBrowserEventEmitter` before
   * the reconciliation.
   */
  initialize: function() {
    var currentlyEnabled = ReactBrowserEventEmitter.isEnabled();
    ReactBrowserEventEmitter.setEnabled(false);
    return currentlyEnabled;
  },
  /**
   * @param {boolean} previouslyEnabled Enabled status of
   *   `ReactBrowserEventEmitter` before the reconciliation occurred. `close`
   *   restores the previous value.
   */
  close: function(previouslyEnabled) {
    ReactBrowserEventEmitter.setEnabled(previouslyEnabled);
  },
};
/**
 * Provides a queue for collecting `componentDidMount` and
 * `componentDidUpdate` callbacks during the transaction.
 */