I have something like this:
$scope.traveler = [
{ description: 'Senior', Amount: 50},
{ description: 'Senior', Amount: 50},
{ description: 'Adult', Amount: 75},
{ description: 'Child', Amount: 35},
{ description: 'Infant', Amount: 25 },
];
Now to have a total Amount of this array I'm doing something like this:
$scope.totalAmount = function(){
var total = 0;
for (var i = 0; i < $scope.traveler.length; i++) {
total = total + $scope.traveler[i].Amount;
}
return total;
}
It's easy when is only one array, but I have others arrays with a different property name that I would like to sum.
I would be happier If I could do something like this:
$scope.traveler.Sum({ Amount });
But I don't know how to go through this in a way that I could reuse it in the future like this:
$scope.someArray.Sum({ someProperty });
Answer
I decided to use @gruff-bunny suggestion, so I avoid prototyping native object (Array)
I just did a little modification to his answer validating the array and the value to sum aren't null, this is my final implementation:
$scope.sum = function (items, prop) {
if (items == null) {
return 0;
}
return items.reduce(function (a, b) {
return b[prop] == null ? a : a + b[prop];
}, 0);
};