Javascript Web API call in for loop

Question

I am developing an app with angularjs and ionic. There I have an array with ids. And from all these ids I need to have a name. Now I tried it with the code below:

var arrayWithIds = [1, 2, 3, 4, 5, 6, 7]
var arrayWithNames = [];

for (var j = 0; j < arrayWithIds.length; j++) {
    ResourceService.get(arrayWithIds[j]).then(function(resource) {
        arrayWithNames.push(resource.Name);                  
    },function(error) {
        alert(error.message);        
    });               
}

$scope.resources = arrayWithNames;

It is all ok when I debug. I always get the name back. But in $scope.resources there is nothing, it is empty, also the array arrayWithNames.

Do I miss something? What is the problem?

Thanks.

Have you tried adding in the return arrayWithNames; at the end of the for loop? See whether that works? — Daniel Chan
– Daniel Chan, Commented Jul 15, 2015 at 7:13
Maybe it is important to say that the whole code above is also in a web api call. — user3679607
– user3679607, Commented Jul 15, 2015 at 7:23

franciscod · Accepted Answer · 2015-07-15 07:34:15Z

2

The ResourceService.get() call is asynchronous (and also a Promise), and this line

$scope.resources = arrayWithNames;

is getting called before the ResourceService.get() callback.

You can drop arrayWithNames and directly push to $scope.resources:

var arrayWithIds = [1, 2, 3, 4, 5, 6, 7]
$scope.resources = [];

for (var j = 0; j < arrayWithIds.length; j++) {
    ResourceService.get(arrayWithIds[j]).then(function(resource) {
        $scope.resources.push(resource.Name);                  
    },function(error) {
        alert(error.message);        
    });               
}

answered Jul 15, 2015 at 7:34

franciscod

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