AngularJS Count Yes/No Values - angularjs

Question

I'm currently working on a AngularJS / Parse.com web application
What I'm trying to achieve:
I would like to get the total amount of Yes & No values within an Array.
e.g Yes = 3 No = 6
Current Problems:
I've managed to get all Yes & No values from Parse and put them into an Array but I'm unable to count the amount of Yes or No values.
Any help / advice would be helpful!
HTML:
<md-card>
<md-card-content>
<canvas id="doughnut" class="chart chart-doughnut" data="widgetone_data" labels="widgetone_label"></canvas>
</md-card-content>
{{widgetone_data | json}}
</md-card>
Controller JS:
dashApp.controller("dashboardCtrl", function ($scope, $http, $filter) {
$scope.parseRecommendations = [];
$http({
method : 'GET',url : 'https://api.parse.com/1/classes/Customers',
headers: { 'X-Parse-Application-Id':'xxx', 'X-Parse-REST-API-Key':'xxx'}
})
.success(function(data, error) {
$scope.parseResults = data.results;
angular.forEach($scope.parseResults, function(results) {
$scope.parseRecommendations.push(results.question_4_p1);
});
})
.error(function(data, error) {alert('Failed, error code: ' + error.message);
});
// Recommend YES/NO
var yesAmount = $filter('filter')($scope.parseRecommendations, { isSelected: 'yes' }).length;
var noAmount = $filter('filter')($scope.parseRecommendations, { isSelected: 'no' }).length;
$scope.widgetone_label = ["Yes", "No"];
$scope.widgetone_data = [yesAmount,noAmount];
});

Answer 1

You can use the .filter() method.
Moreover, you made an error, because you start to filter your data when the controller is instantiated, but your API call is asynchronous, so you have to filter your data into the .success() callback, otherwise you will filter an empty array.
EDIT : To improve performance, you can count your by simulating an hashmap. See below
dashApp.controller("dashboardCtrl", function ($scope, $http, $filter) {
$scope.parseRecommendations = [];
var hashmap = {};
$http({
method : 'GET',url : 'https://api.parse.com/1/classes/Customers',
headers: { 'X-Parse-Application-Id':'wmWxU64vx0QgKBiNQkx9jCDNO6UZDRrM6WkxAbTL', 'X-Parse-REST-API-Key':'0FHcBHZdeUJHKT8j0VQH0hQdN4TZ8qsOBxyd1rG3'}
})
.success(function(data, error) {
$scope.parseResults = data.results;
angular.forEach($scope.parseResults, function(results) {
$scope.parseRecommendations.push(results.question_4_p1);
});
$scope.parseRecommendations.forEach(function(elm){
hashmap.hasOwnProperty(elm)
? ++hashmap[elm]
: hashmap[elm] = 1
});
//Filter yes
var yesAmount = hashmap.yes;
//Filter no
var noAmount = hashmap.no;
$scope.widgetone_label = ["Yes", "No"];
$scope.widgetone_data = [yesAmount,noAmount];
console.log($scope.widgetone_data);
})
.error(function(data, error) {alert('Failed, error code: ' + error.message);
});
});