ngProviderController implements controller resolution using $injector.

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The MIT License

Copyright (c) 2013 Niall Smart

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ngProviderController.js

/*jslint vars: true */
/*global angular: true */


/**
 * ngProviderController implements controller resolution using $injector. It attempts to
 * resolve named controllers using $injector.get, otherwise falling back to the default
 * resolution strategy.
*/
angular.module('ngProviderController', ['ng'], ['$provide', function($provide) {

  "use strict";

  var CNTRL_REG = /^(\S+)(\s+as\s+(\w+))?$/,
      decorator = function($injector, $delegate) {
        return function(expression, locals) {

          var instance, match, constructor, identifier;

          if (angular.isString(expression)) {
            match = expression.match(CNTRL_REG);
            constructor = match[1];
            identifier = match[3];
            if ($injector.has(constructor)) {
              expression = $injector.get(constructor);
              if (!angular.isFunction(expression)) {
                throw new Error('Argument \'' + constructor + '\' is not a function');
              }
            }
          }

          if (angular.isFunction(expression)) {
            instance = $injector.instantiate(expression, locals);

            if (identifier) {
              if (!locals || typeof locals.$scope !== 'object') {
                throw new Error('Can not export controller as "' + identifier + '". ' +
                    'No scope object provided!');
              }

              locals.$scope[identifier] = instance;
            }
          } else {
            instance = $delegate.call(null, expression, locals);
          }

          return instance;
        };
      };

  $provide.decorator('$controller', ['$injector', '$delegate', decorator]);

}]);

ngProviderController.spec.js

/*jslint vars: true, white: true */
/*global beforeEach: true, module: true, describe: true, it: true, expect: true */

describe('ngProviderController', function() {
  "use strict";

  var $provide;
  var $controller;
  var $controllerProvider;
 
  beforeEach(module(function(_$provide_, _$controllerProvider_) {
    $provide = _$provide_;
    $controllerProvider = _$controllerProvider_;
  }));

  beforeEach(module("ngProviderController"));

  beforeEach(inject(function(_$controller_) {
    $controller = _$controller_;
  }));

  it('should return instance of given controller class', function() {
    var MyCtrl = function($scope) {},
        ctrl = $controller(MyCtrl, {$scope: {}});
 
    expect(ctrl).toBeDefined();
    expect(ctrl instanceof MyCtrl).toBe(true);
  });

  it('should return instance from provider', function() {
    var MyCtrl,
        scope = {},
        ctrl;

    $provide.factory("Ctrl", function() {
      return MyCtrl = function($scope, name) {
        $scope.name = name;
      };
    });
    ctrl = $controller("Ctrl", {$scope: scope, name: "dave"});

    expect(ctrl).toBeDefined();
    expect(ctrl instanceof MyCtrl).toBe(true);
    expect(scope.name).toBe("dave");
  });

  it('should publish controller instance into scope', function() {
    var MyCtrl = function() {},
        scope = {},
        ctrl;
    
    $provide.factory("Ctrl", function() {
      return MyCtrl;
    });
    ctrl = $controller("Ctrl as ctrl", {$scope: scope});

    expect(ctrl).toBeDefined();
    expect(ctrl instanceof MyCtrl).toBe(true);
    expect(scope.ctrl).toBe(ctrl);
  });

  it('should throw an error if $scope is not provided', function() {
    $provide.value('Ctrl', function() {});

    expect(function() {
      $controller('Ctrl as ctrl');
    }).toThrow('Can not export controller as "ctrl". No scope object provided!');
  });


  it('should fallback to default resolution strategy', function() {
    var MyCtrl = function($scope, name) { $scope.name = name; },
        scope = {},
        ctrl;

    $controllerProvider.register("Ctrl", MyCtrl);
    ctrl = $controller("Ctrl", {$scope: scope, name: "dave"});

    expect(ctrl).toBeDefined();
    expect(ctrl instanceof MyCtrl).toBe(true);
    expect(scope.name).toBe("dave");
  });

  it('should throw exception if provider doesn\'t return function', function() {

    $provide.factory("Ctrl", function() {
      return "ctrl";
    });

    expect(function() { $controller("Ctrl as c"); }).toThrow("Argument 'Ctrl' is not a function");
  });

});