Not sure why but I can see these messages in the beta bundles:

```
ReactDOM.render(): Invalid component element. Instead of passing a string like 'div', pass React.createElement('div') or <div />.
Missing injection for fiber findDOMNode
Missing injection for stack findDOMNode
Element appears to be neither ReactComponent nor DOMNode. Keys: %s
Target container is not a DOM element.
```

I'd like to understand why.
'objectRestSpread',
  ],
};
module.exports = function(opts) {
  if (!opts || !('errorMapFilePath' in opts)) {
    throw new Error(
      'Missing options. Ensure you pass an object with `errorMapFilePath`.'
    );
  }
  var errorMapFilePath = opts.errorMapFilePath;
  var existingErrorMap;
  try {
    existingErrorMap = require(path.join(
      __dirname,
      path.basename(errorMapFilePath)
    ));
  } catch (e) {
    existingErrorMap = {};
  }
  var allErrorIDs = Object.keys(existingErrorMap);
  var currentID;
  if (allErrorIDs.length === 0) {
    
    currentID = 0;
  } else {
    currentID = Math.max.apply(null, allErrorIDs) + 1;
  }
  
  existingErrorMap = invertObject(existingErrorMap);
  function transform(source) {