Angular orderBy number sorting as text in ng-repeat

Question

I have this data:

[{"id":"42","firstname":"Sarah","lastname":"Dilby","age":"40","cars":"Yaris"},
{"firstname":"Jason","lastname":"Diry","age":"5","id":"5"},
{"id":"6","firstname":"Bilson","lastname":"Berby","age":"1","cars":"Tipo"}]

When I orderBy id or by age in an ng-repeat, it sorts the number as text. Since I can't find it written that this is an issue anywhere, I'm guessing there's a problem with my code. I have created this fiddle: http://jsfiddle.net/vsbGH/1/ Sorry about the template, but jsfiddle doesn't allow in the html box. Anyway, this is the code which loads and sorts the data:

//user data
app.service('People', function() {
var People = {};
People.details = [{"id":"42","firstname":"Sarah","lastname":"Dilby","age":"40","cars":"Yaris"},
                  {"firstname":"Jason","lastname":"Diry","age":"5","id":"5"},
                  {"id":"6","firstname":"Bilson","lastname":"Berby","age":"1","cars":"Tipo"}]
return People;
});

//list ctrl
controllers.listCtrl = function ($scope,People) {
 $scope.people = People.details;

 $scope.sortList = function(sortname) {
    $scope.sorter = sortname;
 }
}

And this is the ng-repeat part of the template:

<tr ng-repeat="person in people | orderBy:sorter ">
        <td>{{person.id | number}}</td>
        <td>{{person.firstname}} </td>
        <td>{{person.lastname}} </td>
        <td>{{person.age | number}}</td>
        <td>{{person.cars}} </td>
 </tr>

Many thanks if you can help me understand why the number data isn't sorting as numbers, and why it's sorting as text.

Answer 1

I think the most appropriate solution is to format the numbers I have on my JSON objects correctly, ie not to wrap them in quotes. So:

 [{"id":"42","firstname":"Sarah","lastname":"Dilby","age":"40","cars":"Yaris"},
  {"firstname":"Jason","lastname":"Diry","age":"5","id":"5"},
  {"id":"6","firstname":"Bilson","lastname":"Berby","age":"1","cars":"Tipo"}]

becomes:

[{"id":42,"firstname":"Sarah","lastname":"Dilby","age":40,"cars":"Yaris"},
 {"firstname":"Jason","lastname":"Diry","age":5,"id":5},
 {"id":6,"firstname":"Bilson","lastname":"Berby","age":1,"cars":"Tipo"}]

I'm guessing SergL's solution is good if it's not possible to correct the format of the JSON data.

To add to this, the issue in my specific case is to do with PHP's json_encode function on the server side. By default, it treats numbers as strings. To fix I had to add the JSON_NUMERIC_CHECK option to the encode method in the PHP script:

json_encode($assoc_array,JSON_NUMERIC_CHECK);