According to the discussion here https://github.com/facebook/react/issues/11502 it is legal to return iterators from `Component.render`. But it is not mentioned in the document. Moreover -- it would work only in production mode, not in development. It should me mentioned that to make it work in both environments -- you should use iterable, rather than iterator (see this `Seq` approach from the Reach issue). I suggest to place it around https://reactjs.org/docs/react-component.html#fragments