How to find the index of an item in an AngularJS array

Question

How to find the index of an item in an AngularJS array

After receiving a set of JSON data from the backend API, I found myself in need of looping through an existing array to extract the index for use with the splice method. In order to achieve this, I decided to utilize the combination of the indexOf method and the filter function provided by Angular.

Although I successfully filtered out the desired data from the array, I encountered difficulty when trying to retrieve the index. Each time I attempted to do so, it resulted in a return of -1.

Below is a snippet showcasing my approach:

JS

angular.forEach($scope.data, function(){
   var index = $scope.Tablelist.indexOf($filter('filter')($scope.Tablelist,{id: $scope.data.id},true));
   console.log($filter('filter')($scope.Tablelist,{id: $scope.data.id},true));
   console.log(index);
})

javascript arrays angularjs

Answer 1

Answer №1

$filter retrieves an array, and the first element needs to be extracted before searching using indexOf:

var index = $scope.Tablelist.indexOf(
                $filter('filter')($scope.Tablelist,{id: $scope.data.id},true)[0]
            );

However, a more efficient method would be utilizing Array.prototype.findIndex(). This approach reduces redundant iterations through the entire Tablelist.

var index = $scope.Tablelist.findIndex(function(item) {
    return item.id === $scope.data.id;
});

Alternatively, employ a standard for loop for broader browser compatibility:

var index = -1;
for (var i = 0; i < $scope.Tablelist.length; i++)
    if ($scope.Tablelist[i].id === $scope.data.id) {
        index = i;
        break;
    }
}

Answer 2

$filter retrieves an array, and the first element needs to be extracted before searching using indexOf:

var index = $scope.Tablelist.indexOf(
                $filter('filter')($scope.Tablelist,{id: $scope.data.id},true)[0]
            );

However, a more efficient method would be utilizing Array.prototype.findIndex(). This approach reduces redundant iterations through the entire Tablelist.

var index = $scope.Tablelist.findIndex(function(item) {
    return item.id === $scope.data.id;
});

Alternatively, employ a standard for loop for broader browser compatibility:

var index = -1;
for (var i = 0; i < $scope.Tablelist.length; i++)
    if ($scope.Tablelist[i].id === $scope.data.id) {
        index = i;
        break;
    }
}

Answer 3

Answer №2

Give this a shot:

let selectedObject = $filter('filter')($scope.Tablelist, function (d) {
   return d.id === $scope.data.id;
})[0];
console.log(selectedObject);
console.log($scope.Tablelist.indexOf(selectedObject));

Answer 4

Give this a shot:

let selectedObject = $filter('filter')($scope.Tablelist, function (d) {
   return d.id === $scope.data.id;
})[0];
console.log(selectedObject);
console.log($scope.Tablelist.indexOf(selectedObject));

Answer 5

Answer №3

$filter('filter')($scope.Tablelist,{id: $scope.data.id},true)

This code snippet returns an array of length 1 instead of the item itself.

$filter('filter')($scope.Tablelist,{id: $scope.data.id},true)[0]

Perhaps using this modification can solve the issue.

Answer 6

$filter('filter')($scope.Tablelist,{id: $scope.data.id},true)

This code snippet returns an array of length 1 instead of the item itself.

$filter('filter')($scope.Tablelist,{id: $scope.data.id},true)[0]

Perhaps using this modification can solve the issue.

Answer 7

Answer №4

$filter function retrieves an array, attempting to locate the index of that array in your Tablelist but if it returns -1, try this instead:

var index =
  $scope.Tablelist.indexOf($filter('filter')($scope.Tablelist,{id: $scope.data.id},true)[0]));

Answer 8

$filter function retrieves an array, attempting to locate the index of that array in your Tablelist but if it returns -1, try this instead:

var index =
  $scope.Tablelist.indexOf($filter('filter')($scope.Tablelist,{id: $scope.data.id},true)[0]));

How to find the index of an item in an AngularJS array

Answer №1

Answer №2

Answer №3

Answer №4

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