Angular Sorting with null objects - angularjs

Question

I need to take records with null values on top , when I'm sorting by ASC
<tr ng-repeat="footballer in footballers=(footballers | orderBy:predicate)">
predicate : ['team.name','id]
Some footballers have no team, so team object == null and team.name==null, and I need to have them on the top
I wanted to rewrite sort function, but I need to save predicate

Answer 1

You can use something like this in your controller:
$scope.nullsToTop = function(obj) {
return (angular.isDefined(obj.team) ? 0 : -1);
};
And on the HTML:
<tr ng-repeat="footballer in footballers | orderBy:[nullsToTop].concat(predicate)">
This way you can maintain your predicate separately. Just concat the nullsToTop function in the orderBy expression to run it first.
Plunker

Answer 2

Create a function in the controller that will receive as parameter the entity and will return either ['team.name','id] either [] or other values that will help push the non-sortable elements to top/bottom of the list.
EDIT (example)
HTML:
<li ng-repeat="item in items | orderBy:getItemOrder track by $index">...
AngularJS Ctrl:
$scope.getItemOrder = function (entity) {
if (entity.id === null || .... === null) {
return 0;
}
return ['team.name','id];
}

Answer 3

I was able to do it by returning a '+' or a '-' if the value is null, close to what bmleite did but is more contained in the function itself.
1. create a function that adds a + or a - to the null values depending on the sort order (asc or desc) so that they'd always remain at either the top or bottom
function compareAndExcludeNull(element){
var compareWith = $scope.order.propertyName; // in your case that's 'predicate'
var operatorToBottom = $scope.order.reverse ? '+' : '-'; // If decending then consider the null values as smallest, if ascending then consider them biggest
var operatorToTop = $scope.order.reverse ? '-' : '+';
if(element[compareWith] == null){
return operatorToTop;
} else {
return operatorToBottom+element[compareWith];
}
}
if you want to have the null values at the bottom of the sorted array then just switch the operatorToTop with operatorToBottom and vice versa to get:
function compareAndExcludeNull(element){
var compareWith = $scope.order.propertyName; // in your case that's '
var operatorToBottom = $scope.order.reverse ? '+' : '-'; // If decending then consider the null values as smallest, if ascending then consider them biggest
var operatorToTop = $scope.order.reverse ? '-' : '+';
if(element[compareWith] == null){
return operatorToBottom;
} else {
return operatorToTop+element[compareWith];
}
}
2. Call the function and pass the array you're sorting
Javascript:
In my case I am calling this function from HTML and passing different propertyName depending on the column the user is sorting by, in your case you'd just need to pass 'predicate' as the propertyName
$scope.order.sortBy = function(propertyName){
$scope.order.reverse = (propertyName !== null && $scope.order.propertyName === propertyName) ? !$scope.order.reverse : false;
$scope.order.propertyName = propertyName;
$scope.resources = $filter('orderBy')($scope.resources,compareAndExcludeNull,$scope.order.reverse);
};
HTML:
<div>
<span ng-if="showKeywords" class="label label-info" ng-click="order.sortBy('keyword')" style="margin-right: 5px">
Order by Keywords
<span ng-if="order.propertyName=='keyword'" class="glyphicon glyphicon-triangle-{{order.reverse? 'bottom' : 'top'}}">
</span>
</span>
<span ng-if="showWebsites" class="label label-info" ng-click="order.sortBy('res_title')">
Order by Website
<span ng-if="order.propertyName=='res_title'" class="glyphicon glyphicon-triangle-{{order.reverse? 'bottom' : 'top'}}">
</span>
</span>
</div>

Answer 4

I know this is an old post but there is a better way for doing this and could not see it anywhere.
var myApp = angular.module('myApp', []);
myApp.controller('myCtrl', ["$scope", function($scope){
$scope.footballers = [
{id: 0, qt: 13},
{id: 1, qt: 2},
{id: 2, qt: 124},
{id: 3, qt: 12125},
{id: null , qt: 122},
{id: 4, qt: -124},
{id: 5, qt: -5235},
{id: 6, qt: 43},
]
}])
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.9/angular.min.js"></script>
<div ng-app="myApp" ng-controller="myCtrl">
<div ng-repeat="footballer in footballers | orderBy:['id==null || id']">
{{footballer.id}}, {{footballer.qt}}
</div>
</div>
One can also use this to show 'id' with any specific value on top of others