闭包编译器，缺少具有高级优化功能的方法？

Question

I'm using the closure compiler in an angularjs application. My JS compiles without errors (or warnings) and works fine with SIMPLE optimizations. Specifically, I have the following warnings/checks enabled:

--jscomp_warning=checkTypes \
--jscomp_error=checkVars \
--jscomp_warning=deprecated \
--jscomp_error=duplicate \
--jscomp_warning=globalThis \
--jscomp_warning=missingProperties \
--jscomp_warning=undefinedNames \
--jscomp_error=undefinedVars \

However, when I try to compile using ADVANCED OPTIMIZATIONS, I get the following error:

TypeError: a.handleEvent is not a function
    at Sj.Nh.a.(anonymous function).a.(anonymous function) (http://localhost:10080/main/pattern.dots-0-7-7-258310cc.compiled.js:118:273)
    at $h (http://app.js:120:424)
    at R (http://app.js:119:337)
    at lj (http://app.js:144:380)
    at Sj.f.re (http://app.js:151:622)
    at mo (http://app.js:302:171)
    at to (http://app.js:316:78)
    at link (http://app.js:308:335)
    ...

which appears to be related to event handling code (from looking at the source map):

/**
 * @param {Object|Function} listener The listener function or an
 *     object that contains handleEvent method.
 * @return {!Function} Either the original function or a function that
 *     calls obj.handleEvent. If the same listener is passed to this
 *     function more than once, the same function is guaranteed to be
 *     returned.
 */
goog.events.wrapListener = function(listener) {
  goog.asserts.assert(listener, 'Listener can not be null.');

  if (goog.isFunction(listener)) {
    return listener;
  }

  goog.asserts.assert(
      listener.handleEvent, 'An object listener must have handleEvent method.');
  if (!listener[goog.events.LISTENER_WRAPPER_PROP_]) {
    listener[goog.events.LISTENER_WRAPPER_PROP_] =
        function(e) { return listener.handleEvent(e); };
  }
  return listener[goog.events.LISTENER_WRAPPER_PROP_];
};

But this seems really odd. After all, there's an assert a couple lines up that (apparently) passes. I think I've tried to keep the assert ( -D goog.asserts.ENABLE_ASSERTS ) and even if the assert is optimized away, I don't understand why it would work with SIMPLE optimizations (where the assert would still be present). Also, the code still works if I compile with advanced optimizations and --debug , which looks like it starts the process of namespace collapsing, but doesn't go all the way.

Interestingly enough, if I try adding some console.log statements:

goog.events.wrapListener = function(listener) {
  goog.asserts.assert(listener, 'Listener can not be null.');

  if (goog.isFunction(listener)) {
    return listener;
  }

  goog.asserts.assert(
      listener.handleEvent, 'An object listener must have handleEvent method.');
  if (!listener[goog.events.LISTENER_WRAPPER_PROP_]) {
    listener[goog.events.LISTENER_WRAPPER_PROP_] =
        function(e) {
          console.log(e);
          console.log(listener);
          console.log(typeof listener);
          console.log(listener.handleEvent);
          console.log(typeof listener.handleEvent);
          return listener.handleEvent(e);
        };
  }
  return listener[goog.events.LISTENER_WRAPPER_PROP_];
};

And I see that the typeof listener is 'function' . But if that's the case, how did we get here in the first place? (certainly goog.isFunction(listener) should have returned true at that point ...).

I'm a bit at a loss as to what might be going on here...

Answer 1

Well, It seems that after countless hours of trying to debug this one, the answer falls into my lap right after I post the question (again).

I was unlucky enough to have goog.isFunction compile down to the symbol ga -- which conflicts with the global usage tracking library "Google Analytics".

The solution for me was to just include the universal_analytics_api.js in my externs and all seems to be well with the world.