Add a key to an object with keys of an existing array with objects

Question

I've got an array of objects array = [object1, object2, ...], each of them has some keys object1 = { key1: 'value1', ... }. I want to add a key this way:

$rootScope.array[i].newKey = 'someValue'

But angular tells me that $rootScope.array[i] is undefined.

What I've noticed from console is that the objects get the new key but the console still says the same.

did you add the array to your $rootScope ? like $rootScope.array = array; — Lulylulu
– Lulylulu, Commented Mar 30, 2016 at 14:38
this means that meat types is an array that contains one empty object. To declare an empty array just use $rootScope.meatTypes = [] — Lulylulu
– Lulylulu, Commented Mar 30, 2016 at 14:59

Lulylulu · Accepted Answer · 2016-03-30 15:06:35Z

3

You should use less than and not less or equal than comparator.

  $scope.init = function () {
        for (i = 0; i < /* not <= */ $rootScope.meatTypes.length; i++) {
            console.log("I am showing the meatypes:");
            console.log($rootScope.meatTypes);
            $rootScope.meatTypes[i].counter = '0';
            counterOperations.setCounters(i, 0);
        }
        $rootScope.total = 0;
        counterOperations.setTopCounter(0);
    };

because when i equals $rootScope.meatTypes.length then $rootScope.meatTypes[i] is undefined.

edited Mar 30, 2016 at 15:06

answered Mar 30, 2016 at 15:00

Lulylulu

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Comments

David L · Accepted Answer · 2016-03-30 14:38:37Z

2

You are trying to access a member of the array that does not exist.

You need to create a new object and push it onto the array:

$rootScope.array.push({'key1': 'someValue'});

answered Mar 30, 2016 at 14:38

David L

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2 Comments

korteee Over a year ago

I need to create a new key in an existing object of my array not to create a new object.

korteee Over a year ago

When I actually do this my browser crashes: ` $scope.init = function () { for (i = 0; i <= $rootScope.meatTypes.length; i++) { console.log("I am showing the meatypes:"); console.log($rootScope.meatTypes); $rootScope.meatTypes.push({'counter':0}); counterOperations.setCounters(i, 0); } $rootScope.total = 0; counterOperations.setTopCounter(0); }; `

random_user_name · Accepted Answer · 2016-03-30 15:13:27Z

1

You did not mention lodash, but when I see someone encounter an issue like this, I want to offer the recommendation of using lodash (or underscore.js).

With lodash, you would do something like so, using _.set, which defensively protects against your described issue by automatically adding the necessary elements in the path:

_.set($rootScope, ['array', i, 'newKey'], 'someValue');

This library, properly utilized, solves many issues that you can have with setting and getting variables, ase well as other super useful tools. It has been a major life-saver (and time-saver) for us on our projects.

answered Mar 30, 2016 at 15:13

random_user_name

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Comments

saravanakumar · Accepted Answer · 2016-03-30 15:01:07Z

0

Like this you can add

$rootScope.array[i] = {}; // first we should create an object on that array location
$rootScope.array[i]['newKey'] = 'someValue'; // then only we can add values

EDIT:

$scope.init = function () {
    for (i = 0; i <= $rootScope.meatTypes.length; i++) {
        console.log("I am showing the meatypes:");
        console.log($rootScope.meatTypes);
        **// This is needed**
        $rootScope.meatTypes[i]={};// here we should tell that metaType[newItem] is an object other wise it treat it as undefined
        $rootScope.meatTypes[i].counter = '0';
        counterOperations.setCounters(i, 0);
    }
    $rootScope.total = 0;
    counterOperations.setTopCounter(0);
};

edited Mar 30, 2016 at 15:01

answered Mar 30, 2016 at 14:54

saravanakumar

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