Babel es2015 preset in loose mode without frills, made for Rollup.
$ npm i -S babel-preset-es2015 babel-preset-es2015-minimal-rollup
.babelrc
{
"presets": ["es2015-minimal-rollup"]
}
$ babel script.js --presets es2015-minimal-rollup
require('babel-core').transform('code', {
presets: ['es2015-minimal-rollup']
});