Verify the existence of the object before adding it to the array

Question

Verify the existence of the object before adding it to the array

Looking to iterate through a JSON response in order to verify the existence of a key/value pair, and if not present, include it in the array.

  $scope.InitProdToArray = function (data) {
    angular.forEach($scope.data.obj.Product, function(value, index) {

        if (value.Product_type != 'T' ) {
            $scope.data.obj.Product.push({Product_type: 'T'});
        }
        if (value.Product_type != '16364NB' ) {
            $scope.data.obj.Product.push({Product_type: '16364NB'});
        }
        if (value.Product_type != '39087NB' ) {
            $scope.data.obj.Product.push({Product_type: '39087NB'});
        }
        if (value.Product_type != 'C' ) {
            $scope.data.obj.Product.push({Product_type: 'C'});
        }
        if (value.Product_type != '4NB' ) {
            $scope.data.obj.Product.push({Product_type: '4NB'});
        }        
    });

  JSON: $scope.data.obj.Product = 
                    [{
                        "Count": 28,
                        "Product_type": "T"
                    }, {
                        "Count": 88,
                        "Product_type": "4NB"
                    }, {
                        "Count": 20,
                        "Product_type": "C"
                    }, {
                        "Count": 3,
                        "Product_type": "39087NB"
                    }
                ]

This method is currently ineffective as I am duplicating product_type values in the resultant JSON by pushing the key/value pairs for each iteration. Is there a way to prevent duplicate entries from being added?

javascript angularjs arrays json

Answer 1

Answer №1

It appears as though your type check may be flipped around. Instead of using

if (value.Product_type != 'T' ) {...

, consider utilizing

if (value.Product_type == 'T' ) {...

. This way, you'll only add to the Product array when the type matches.

In addition to that, you can also verify before adding if the Product array already includes a key of that type:

if($scope.data.obj.Product.indexOf(value.Product_type)!==undefined)

Answer 2

It appears as though your type check may be flipped around. Instead of using

if (value.Product_type != 'T' ) {...

, consider utilizing

if (value.Product_type == 'T' ) {...

. This way, you'll only add to the Product array when the type matches.

In addition to that, you can also verify before adding if the Product array already includes a key of that type:

if($scope.data.obj.Product.indexOf(value.Product_type)!==undefined)

Answer 3

Answer №2

It appears from your code that you are focusing on search and insert operations rather than dealing with key/value pairs.

If you are targeting modern browsers, there is a useful function called find that can be used for this purpose.

var productTypes = ['T', '16364NB', '39087NB', 'C', '4NB'];

angular.forEach(productTypes, function(value) {
    var exists = $scope.data.obj.Product.find(function(item) {
        return (item.Product_type == value);
    });

    if (!exists) {
        $scope.data.obj.Product.push({
            Product_type: value,
            count: 0
        });
    }
});

For older browser support, it's recommended to include a polyfill for the find function as well.

Answer 4

It appears from your code that you are focusing on search and insert operations rather than dealing with key/value pairs.

If you are targeting modern browsers, there is a useful function called find that can be used for this purpose.

var productTypes = ['T', '16364NB', '39087NB', 'C', '4NB'];

angular.forEach(productTypes, function(value) {
    var exists = $scope.data.obj.Product.find(function(item) {
        return (item.Product_type == value);
    });

    if (!exists) {
        $scope.data.obj.Product.push({
            Product_type: value,
            count: 0
        });
    }
});

For older browser support, it's recommended to include a polyfill for the find function as well.

Answer 5

Answer №3

var CATEGORIES = { A: 'A', B1: '1B', X: 'X', Y2Z: '2YZ'};
var items = [{ "Count": 28, "Category_type": "A" }, { "Count": 88, "Category_type": "1B" }];

/* verifying if the element key is not set to a specific value....*/
function checkKeyInElement(keyToVerify, element) {
return element.Category_type === keyToVerify;
}

/* checking for the absence of elements in array with the specified key ...*/
function noElementsWithKeyinArray(keyToCheck, arr) {
return !!arr.filter(function (element) { return checkKeyInElement(keyToCheck, element); }).length;
}

/* an alternative method to confirm the absence of elements in array with the specified key ...*/
function noElementsWithKeyinArray2(keyToConfirm, arr) {
return arr.map(function (element) { return element.Category_type; }).indexOf(keyToConfirm) > -1;
}

function initItemsToArray(sourceArr) {
if (!noElementsWithKeyinArray(CATEGORIES.A, sourceArr)) { sourceArr.push({ Category_type: CATEGORIES.A }); }
if (!noElementsWithKeyinArray(CATEGORIES.B1, sourceArr)) { sourceArr.push({ Category_type: CATEGORIES.B1 }); }
if (!noElementsWithKeyinArray(CATEGORIES.X, sourceArr)) { sourceArr.push({ Category_type: CATEGORIES.X }); }
if (!noElementsWithKeyinArray(CATEGORIES.Y2Z, sourceArr)) { sourceArr.push({ Category_type: CATEGORIES.Y2Z }); }
}

initItemsToArray(items);
console.log(items);

Answer 6

var CATEGORIES = { A: 'A', B1: '1B', X: 'X', Y2Z: '2YZ'};
var items = [{ "Count": 28, "Category_type": "A" }, { "Count": 88, "Category_type": "1B" }];

/* verifying if the element key is not set to a specific value....*/
function checkKeyInElement(keyToVerify, element) {
return element.Category_type === keyToVerify;
}

/* checking for the absence of elements in array with the specified key ...*/
function noElementsWithKeyinArray(keyToCheck, arr) {
return !!arr.filter(function (element) { return checkKeyInElement(keyToCheck, element); }).length;
}

/* an alternative method to confirm the absence of elements in array with the specified key ...*/
function noElementsWithKeyinArray2(keyToConfirm, arr) {
return arr.map(function (element) { return element.Category_type; }).indexOf(keyToConfirm) > -1;
}

function initItemsToArray(sourceArr) {
if (!noElementsWithKeyinArray(CATEGORIES.A, sourceArr)) { sourceArr.push({ Category_type: CATEGORIES.A }); }
if (!noElementsWithKeyinArray(CATEGORIES.B1, sourceArr)) { sourceArr.push({ Category_type: CATEGORIES.B1 }); }
if (!noElementsWithKeyinArray(CATEGORIES.X, sourceArr)) { sourceArr.push({ Category_type: CATEGORIES.X }); }
if (!noElementsWithKeyinArray(CATEGORIES.Y2Z, sourceArr)) { sourceArr.push({ Category_type: CATEGORIES.Y2Z }); }
}

initItemsToArray(items);
console.log(items);

Verify the existence of the object before adding it to the array

Answer №1

Answer №2

Answer №3

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