Babel preset for all es2015 plugins without 'use strict' prepend.
$ npm install --save-dev babel-preset-es2015-without-strict
.babelrc
{
"presets": ["es2015-without-strict"]
}
$ babel script.js --presets es2015-without-strict
require("babel-core").transform("code", {
presets: ["es2015-without-strict"]
});