Discover the object in the initial array that is not included in the second array using AngularJS

Question

Discover the object in the initial array that is not included in the second array using AngularJS

Imagine having these two sets of objects:

first set:

[
    {
        id: "123",
        title: "123",
        options: []
    },
    {
        id: "456",
        title: "456",
        options: [
            {
                id: "0123",
                title: "0123",
                options: []
            }
        ]
    },
    {
        id: "789",
        title: "789",
        options: []
    },
]

and the second set:

[
    {
        id: "123",
        title: "123",
        options: []
    },
    {
        id: "789",
        title: "789",
        options: []
    },
]

In the second array, a part is missing:

{ id: "456", title: "456", options: [ { id: "0123", title: "0123", options: [] } ] }

What would be the correct and efficient method to iterate through and identify missing elements in Angular?

javascript arrays angularjs

Answer 1

Answer №1

If you want to achieve this, consider the following approach:

<div ng-app>
    <div ng-controller="MyCtrl">{{availableGroups}}
    </div>
</div>

JavaScript code snippet:

function MyCtrl ($scope) {
    $scope.groups = [
    {
        id: "123",
        title: "123",
        options: []
    },
    {
        id: "456",
        title: "456",
        options: [
            {
                id: "0123",
                title: "0123",
                options: []
            }
        ]
    },
    {
        id: "789",
        title: "789",
        options: []
    },
];

    $scope.assignedGroups = [
    {
        id: "123",
        title: "123",
        options: []
    },
    {
        id: "789",
        title: "789",
        options: []
    },
];


    $scope.availableGroups = (function () {
        var assignedGroupsIds = {};
        var groupsIds = {};
        var result = [];

        $scope.assignedGroups.forEach(function (el, i) {
          assignedGroupsIds[el.id] = $scope.assignedGroups[i];
        });

        $scope.groups.forEach(function (el, i) {
          groupsIds[el.id] = $scope.groups[i];
        });

        for (var i in groupsIds) {
            if (!assignedGroupsIds.hasOwnProperty(i)) {
                result.push(groupsIds[i]);
            }
        }

        return result;    
    }());
}

To see a working example, click on this jsFiddle link.

Thank you.

Answer 2

If you want to achieve this, consider the following approach:

<div ng-app>
    <div ng-controller="MyCtrl">{{availableGroups}}
    </div>
</div>

JavaScript code snippet:

function MyCtrl ($scope) {
    $scope.groups = [
    {
        id: "123",
        title: "123",
        options: []
    },
    {
        id: "456",
        title: "456",
        options: [
            {
                id: "0123",
                title: "0123",
                options: []
            }
        ]
    },
    {
        id: "789",
        title: "789",
        options: []
    },
];

    $scope.assignedGroups = [
    {
        id: "123",
        title: "123",
        options: []
    },
    {
        id: "789",
        title: "789",
        options: []
    },
];


    $scope.availableGroups = (function () {
        var assignedGroupsIds = {};
        var groupsIds = {};
        var result = [];

        $scope.assignedGroups.forEach(function (el, i) {
          assignedGroupsIds[el.id] = $scope.assignedGroups[i];
        });

        $scope.groups.forEach(function (el, i) {
          groupsIds[el.id] = $scope.groups[i];
        });

        for (var i in groupsIds) {
            if (!assignedGroupsIds.hasOwnProperty(i)) {
                result.push(groupsIds[i]);
            }
        }

        return result;    
    }());
}

To see a working example, click on this jsFiddle link.

Thank you.

Answer 3

Answer №2

If we have two arrays, let's call the first one 'first' and the second one 'second'. We can start by sorting both of them:

function sortFunction(a, b){
    if(a.id < b.id) return -1;
    if(a.id > b.id) return 1;
    return 0;
}

first.sort(sortFunction);
second.sort(sortFunction);

Next, we can go through each array to identify any missing elements:

var missingElements = {};
for(var i = 0, j = 0; i < first.length; ++i){
    if(first[i].id == second[j].id){
        j++;
        continue;
    }
    missingElements.push(first[i]);
}

The 'missingElements' array will now contain objects that are present in the first array but not in the second.

It's important to note that this code does not rely on AngularJS; it is written in plain Javascript.

Answer 4

If we have two arrays, let's call the first one 'first' and the second one 'second'. We can start by sorting both of them:

function sortFunction(a, b){
    if(a.id < b.id) return -1;
    if(a.id > b.id) return 1;
    return 0;
}

first.sort(sortFunction);
second.sort(sortFunction);

Next, we can go through each array to identify any missing elements:

var missingElements = {};
for(var i = 0, j = 0; i < first.length; ++i){
    if(first[i].id == second[j].id){
        j++;
        continue;
    }
    missingElements.push(first[i]);
}

The 'missingElements' array will now contain objects that are present in the first array but not in the second.

It's important to note that this code does not rely on AngularJS; it is written in plain Javascript.

Discover the object in the initial array that is not included in the second array using AngularJS

Answer №1

Answer №2

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