Compare dates with momentsjs in angularjs

I can not prove it but I think this will work for you

$scope.a="26-04-2016";    
$scope.c = moment($scope.a,"DD-MM-YYYY").format("YYYY-MM-DD");
$scope.b="20-10-2016";
$scope.d = moment($scope.b,"DD-MM-YYYY").format("YYYY-MM-DD");
if($scope.d <= $scope.c){
    alert($scope.d+' es menor a '+$scope.c)
}else{
    alert($scope.d+' es mayor a '+$scope.c)
}

You can also compare them as JSON, that is:

if($scope.d.toJSON() <= $scope.d.toJSON())

Yesterday I tried it with Angular and it worked:)

.format () converts the date (the moment object) to a text string. If you use the standard format, when ordered by year, month, day, there would be no problem. But you are indicating that the output format is day, month year, so when comparing the text strings it will treat them as numbers, not dates, so 26042016 is larger than 20102016.

The solution is to compare the moment objects directly, or with the moment comparison functions: isBefore () and isAfter (). Then the format you give it at the time of showing the variable.

$scope.a="26-04-2016";    
$scope.c = moment($scope.a,"DD-MM-YYYY");
$scope.b="20-10-2016";
$scope.d = moment($scope.b,"DD-MM-YYYY");
if($scope.d <= $scope.c){
    alert($scope.d.format("YYYY-MM-DD") + ' es menor a  '+ $scope.c.format("YYYY-MM-DD"))
}else{
    alert($scope.d.format("YYYY-MM-DD") + ' es mayor a ' + $scope.c.format("YYYY-MM-DD"))
}

The problem is this:

// Creas un String con la fecha
$scope.a="26-04-2016"; 

$scope.c = 
    // Creas un objeto moment a partir de ese String
    moment($scope.a,"DD-MM-YYYY")

    // Vuelves a convertir dicho objeto moment a String
    // que es exactamente igual a $scope.a
    .format("DD-MM-YYYY");

    // String --> moment --> String

This is redundant and it is also the cause that you are comparing the dates as strings of characters, not as objects Date of javascript and when you compare chains these will give you more or less according to a comparison algorithm that follows different steps (step 4) that if both operands of the algorithm were dates (step 3).

var $scope = {};

$scope.a = "26-04-2016";
$scope.b = "20-10-2016";

$scope.a1 = new Date('2016-04-26');
$scope.b1 = new Date('2016-10-20');

//$scope.a >= $scope.b => true
console.log('$scope.a >= $scope.b :', $scope.a >= $scope.b);
// "26" >= "20" => true
console.log('"26" >= "20" :', "26" >= "20");
//$scope.a1 >= $scope.b1 => false
console.log('$scope.a1 >= $scope.b1 :', $scope.a1 >= $scope.b1);

So the possible solutions can be

angular.module('app', [])
  .controller('DateCtrl', function($scope) {

    $scope.a = "26-04-2016";
    $scope.c = moment($scope.a, "DD-MM-YYYY");
    $scope.b = "20-10-2016";
    $scope.d = moment($scope.b, "DD-MM-YYYY");

    if ($scope.d.isSameOrBefore($scope.c)) {
      alert($scope.b + ' es menor a ' + $scope.a)
    } else {
      alert($scope.b + ' es mayor a ' + $scope.a)
    }

  });

<script src="http://momentjs.com/downloads/moment.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="app" ng-controller="DateCtrl">
  {{a}}
  <br>{{b}}
</div>

angular.module('app', [])
  .controller('DateCtrl', function($scope) {
    // Tambien puedes descomponer las fechas y crear el objeto Date directamente
    $scope.a = "26-04-2016";
    $scope.c = moment($scope.a, "DD-MM-YYYY").toDate();
    $scope.b = "20-10-2016";
    $scope.d = moment($scope.b, "DD-MM-YYYY").toDate();

    if ($scope.d <= $scope.c) {
      alert($scope.b + ' es menor a ' + $scope.a)
    } else {
      alert($scope.b + ' es mayor a ' + $scope.a)
    }

  });

<script src="http://momentjs.com/downloads/moment.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div ng-app="app" ng-controller="DateCtrl">
  {{a}}
  <br>{{b}}
</div>

Finally I recommend that you manipulate your dates using the format ISO 8601 . This is not mandatory but it is the standard and this will save you having to do many date format conversions in your programs.