Question

Why does the Closure Compiler generate different code (using advance option) for the following two functions:

  var function1 = function() {
        return 1 * Math.random();
  };

  window['function1'] = function1;  // export function1

  var function2 = function() {
        return function1() + 1;
  };

  window['function2'] = function2;  // export function2

This is the code generated:

  function a() {
        return 1 * Math.random();
  }

  window.function1 = a;

  window.function2 = function() {
        return a() + 1;  // call to a() fails in a more complex example
  };

Notice that function1 has been renamed to a and a is assigned to the global varible function1. With function2 there is no other variable name associated with it. Why?

The reason why I ask is, in the case with my code, the call to function1 from function2 fails because the renamed function1 is not seen as a function call in function2 but rather the Javascript interpreter thinks that a() is a number.

Any insight is appreciated. TIA.

Answer 1

If “a” is a number, most likely it is getting overwritten by something else. If you aren’t using multiple modules, try using the output wrapper option to isolate the globals (There are other options to isolate globals if you are using multiple modules). Often defining a setter on “windows.a” and setting a break point there will let you know how this overwrite is happening.