Check if obj exist and push to array

Question

I want to iterate through a JSON response, check to see if key,value exists and if not, add it to 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 doesn't seem to work because I'm pushing the key,value pair every time it iterates through each node. I end up getting back a JSON that has multiple product_type that is the same.

Is there a way to stop the code from adding additional key,value if it already exists?

Yes, you can first check whether the key exists in an array of object. — choz, Jan 23 '17 at 05:37
http://stackoverflow.com/questions/1098040/checking-if-a-key-exists-in-a-javascript-object How to check — A. L, Jan 23 '17 at 05:44

score 1 · Answer 1 · answered Jan 23 '17 at 05:52

You seem to have written your type check upside down. instead of if (value.Product_type != 'T' ) {... I would have imagine something like if (value.Product_type == 'T' ) {... this way you would push to Product array only when the type is matching.

apart from that, you can also check before pushing if you Product array already contains a key of that type : if($scope.data.obj.Product.indexOf(value.Product_type)!==undefined)

score 0 · Answer 2 · answered Jan 23 '17 at 05:55

From your code it seems like you are doing search and insert rather than things to do with key/value.

If you are supporting new browsers only there is a handy function called find 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
        });
    }
});

If you need to support older browsers, you'll need to add polyfill for find as well.

score 0 · Answer 3 · answered Jan 23 '17 at 06:06

var TYPES = { T: 'T', NB4: '4NB', C: 'C', NB39087: '39087NB' };
var products = [{ "Count": 28, "Product_type": "T" }, { "Count": 88, "Product_type": "4NB" }];

/* check if the element key is not the specified value....*/
function isKeyInElement(keyToCheck, element) {
 return element.Product_type === keyToCheck;
}

/* checks if there are NO elements in array with the specified key ...*/
function isKeyInArray(keyToCheck, array) {
 return !!array.filter(function (element) { return isKeyInElement(keyToCheck, element); }).length;
}

/* another way to check if there are NO elements in array with the specified key ...*/
function isKeyInArray2(keyToCheck, array) {
 return array.map(function (element) { return element.Product_type; }).indexOf(keyToCheck) > -1;
}

function initProdToArray(source) {
 if (!isKeyInArray(TYPES.T, source)) { source.push({ Product_type: TYPES.T }); }
 if (!isKeyInArray(TYPES.NB4, source)) { source.push({ Product_type: TYPES.NB4 }); }
 if (!isKeyInArray(TYPES.C, source)) { source.push({ Product_type: TYPES.C }); }
 if (!isKeyInArray(TYPES.NB39087, source)) { source.push({ Product_type: TYPES.NB39087 }); }
}

initProdToArray(products);
console.log(products);

Check if obj exist and push to array

3 Answers3