Reserved keywords as properties of module.exports are transpiled into named exports, which causes "unexpected token" errors.

[lxe]

Consider:

module.exports.delete = 'foo';

This will get transpiled into:

var delete = 'foo';

var mycjsmodule = {
    delete: delete
};

export default mycjsmodule;
export { mycjsmodule as __moduleExports };
export { delete };

Which will cause a SyntaxErrors on var delete = 'foo'; and export { delete };

Since it's impossible to do import { delete } from './mycjsmodule' anyways, it would be safe to not create named exports for reserved-keyword properties of module.exports. EDIT: Apparently it's possible to import a reserved keyword like that, as long as it's destructured, at least according to babel! Not sure if that's desired behavior.

[lxe]

According to babel, this is valid es2015:

import { this } from 'wat'

const foo = 'wat';
export { lol as const };

This is madness!

[Rich-Harris]

This is madness!

Seconded! In any case, this should be fixed now in 6.0.0. Thanks