I have an SFC written as a named function, so it can be default-exported with the name intact:

export default function PopoverConfirmedButton({...}) { ... }

This gets transformed into

export default const PopoverConfirmedButton: React.SFC<PopoverConfirmedButtonProps> = ({...}) { ... }

which is not a valid ES export statement, so the Prettier step chokes and I get Failed to convert js/components/PopoverConfirmedButton.jsx.

The correct transformation would probably be

const PopoverConfirmedButton: React.SFC<PopoverConfirmedButtonProps> = ({...}) { ... }
export default PopoverConfirmedButton;