minifier.js

var uglify;

meteorJsMinify = function (source) {
  var result = {};
  uglify = uglify || Npm.require("uglify-es");

  try {
    result.code = uglify.minify(source, {
      /*fromString: true,*/
      compress: {
        drop_debugger: false,
        unused: false,
        dead_code: false,
        comparisons: false,
        //ecma: 6,
        //arrows: false
      },
      output: {
        preamble: "/*uglify-es*/"
      }
    }).code;

  } catch (e) {
    console.error('Uglify failed, falling back to Babel', e, result.code);
    // Although Babel.minify can handle a wider variety of ECMAScript
    // 2015+ syntax, it is substantially slower than UglifyJS, so we use
    // it only as a fallback.
    result.code = Babel.minify(source).code;
  }

  return result;
};