Babel preset for all es2015 plugins and allow top level this.
$ npm install --save-dev babel-preset-es2015-allow-top-level-this
.babelrc
{
"presets": ["es2015-allow-top-level-this"]
}
$ babel script.js --presets es2015-allow-top-level-this
require("babel-core").transform("code", {
presets: ["es2015-allow-top-level-this"]
});