rollup/src/finalisers/es6.js

import { keys } from '../utils/object';

export default function es6 ( bundle, magicString, exportMode, options ) {
	const introBlock = ''; // TODO...

	const exports = bundle.entryModule.exports;
	const exportBlock = keys( exports ).map( exportedName => {
		const specifier = exports[ exportedName ];

		const canonicalName = bundle.entryModule.getCanonicalName( specifier.localName );

		if ( exportedName === 'default' ) {
			return `export default ${canonicalName};`;
		}

		return exportedName === canonicalName ?
			`export { ${exportedName} };` :
			`export { ${canonicalName} as ${exportedName} };`;
	}).join( '\n' );

	if ( exportBlock ) {
		magicString.append( '\n\n' + exportBlock );
	}

	return magicString.trim();
}