AngularJS $timeout call function vs anonymous function vs expression

Question

var four = function() {
    $scope.text += '4';
}

var five = function() {
    $scope.text += '5';
}

$scope.text = '1';

$timeout(function () {
    $scope.text += '2'
});

$timeout($scope.text += '3');

$timeout($scope.$eval(four));

$timeout(five);

Result: 13425

According the call sequence the result should be 12345. The lines below are executed immediately:

$timeout($scope.text += '3');
$timeout($scope.$eval(four));

And if you add the time parameter like below, the time is ignored.

$timeout($scope.text += '3', 1000);
$timeout($scope.$eval(four), 1000);

https://jsfiddle.net/uj9yx9c7/1/

That's how JavaScript works. That's why $timeout takes a function — taguenizy
– taguenizy, Commented Nov 25, 2016 at 13:25

balajisoundar · Accepted Answer · 2016-11-25 13:44:08Z

4

$timeout($scope.text += '3');

in this line $scope.text += '3' is not a function , but an expression. so it will get executed after $scope.text = '1';.

To defer a statement, you need to wrap that statement with a function and pass it $timeout or setTimeout. you can't defer a statement.

Replace $timeout($scope.text += '3'); with $timeout(function(){$scope.text += '3'}). you will get the output 14235.

And $scope.$eval() evaluates a function or an expression synchronously so 4 will get added before 235. changing it to

$timeout(function(){$scope.$eval(four)})

will get the expected output 12345

answered Nov 25, 2016 at 13:44

balajisoundar

5712 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

AngularJS $timeout call function vs anonymous function vs expression

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related