...Files in the stream are annotated with a babel property, which contains the metadata from babel.transform(). If you're attempting to use features such as generators, you'll need to add transform-runtime as a plugin, to include the Babel runtime. Otherwise, you'll receive an error. Options can be passed to Babel in a variety of ways. When passed directly to Babel, you can just pass the options object. When Babel is used via a wrapper, it may also be necessary, or at least more useful, to pass the options via configuration files. ...