Google DCE Method

Before.js

// ==ClosureCompiler==
// @compilation_level ADVANCED_OPTIMIZATIONS
// @output_file_name default.js
// ==/ClosureCompiler==

/**
 * @constructor
 */
function Foo(name) {
  this.name = name;
}

Foo.prototype.foo = function() {
  return this.name;
}

window.x = new Foo('test');

Compiled.js

window.x=new function(a){this.name=a}("test");