AngularJS: weird design or brilliant idea?

Posted on September 22, 2013

Ahem, I have always thought the difference between parameters and arguments are there for a reason and I can use an arbitrary parameter name for my function. It’s probably called a local scope. Well, not AngularJS $scope:

window.SomeCtrl = function($scope) { ... }  //works
window.SomeCtrl = function($myScope) { ... } //doesn't work

The reason why the latter doesn’t work is because AngularJs pretends to be source code parser:

if (typeof fn == 'function') {
  if (!($inject = fn.$inject)) {
    $inject = [];
    fnText = fn.toString().replace(STRIP_COMMENTS, '');
    argDecl = fnText.match(FN_ARGS);
    forEach(argDecl[1].split(FN_ARG_SPLIT), function(arg){
      arg.replace(FN_ARG, function(all, underscore, name){
    fn.$inject = $inject;

Not that I’m against reflection, but this looks like a super-reflection. Next step in this direction would be to modify source code on the fly and re-eval it.