angularJS controllers functions callback

Question

I am wondering how callbacks works in angularJS. I have this code working perfectly like this

$scope.loginFB = function () {
  hello(FACEBOOK).login(function () {
    hello(FACEBOOK).api('me').then(function (profile) {
      console.log('successful api call');
      dbService.handle_credentials(profile);
      $rootScope.$apply(function () {
        $location.path('/homePage');
      });
    }, function(){
      console.error('something went wrong with authentification');
    });
  });
};

but works in weird way when refactored like this

$scope.loginHandler =function () {
  hello(FACEBOOK).api('me').then(function (profile) {
    console.log('successful api call');
    dbService.handle_credentials(profile);
    $rootScope.$apply(function () {
      $location.path('/homePage');
    });
  }, function(){
    console.error('something went wrong with authentification');
  });
};

$scope.loginFB = function () {
  hello(FACEBOOK).login($scope.loginHandler());
};

please tell me what i am doing wrong with this refactoring.

David L · Accepted Answer · 2015-10-01 20:25:08Z

3

By including the params, you are immediately invoking your function callback rather than passing a function reference, which is what you really want to do.

$scope.loginFB = function () {
    hello(FACEBOOK).login($scope.loginHandler);
};

If you want to pass a parameter to your callback function, you can use one of two approaches.

Wrap your callback in an anonymous function

$scope.loginFB = function () {
    hello(FACEBOOK).login(function() { return $scope.loginHandler(param); });
};

In a modern browser, use .bind().

$scope.loginFB = function () {
    hello(FACEBOOK).login($scope.loginHandler.bind(this, param)));
};

edited Oct 1, 2015 at 20:25

answered Sep 30, 2015 at 20:06

David L

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1 Comment

Med Tumy Over a year ago

but what is i want to send parameter to the function. imagine i want to call $scope.loginHandler(param), how do i do that ?

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