Angular: Controller is undefined when adding a directive

Question

I get the following error when adding a directive to my site:

Error: [ng:areq] Argument \'MainController\' is not a function, got undefined

The

Answer 1

You are redefining the module. Define module only once.

when used as angular.module('my-app', []) it defined the module this should be used only once. When you want retrieve it. then use angular.module('my-app')

Use

angular.module('my-app')  //Notice remove []
  .directive("welcome", function() {
  });

Answer 2

passing a 2nd argument like this angular.module('my-app', []) creates a new module, use it only once.

To retrive a module use var module = angular.module('my-app') and use module.controller(... or module.directive(.... etc.,