Do I need to define an array object when populating it with a ForEach in Javascript?

Question

I have the following code:

if (!$scope.aa.hasOwnProperty('x')) {
    $scope.aa.x = {}
    data.answers.forEach(function (element, index) {
        $scope.aa.x[index].c = null;
        $scope.aa.x[index].r = null;
        $scope.aa.x[index].text = element.text;
    });
}

But it gives me an error:

TypeError: Cannot set property 'c' of undefined

Do I need to define an array for aa and if so how can I do this?

Answer 1

An alternative, more idiomatic version of CD's answer is:

$scope.aa.x[index] = {
    c : null,
    r : null,
    text : element.text
}

Answer 2

Yes. looks like x is an array and x[index] is an object :

        $scope.aa.x = [];
        data.answers.forEach(function (element, index) {
            $scope.aa.x[index] = {};
            $scope.aa.x[index].c = null;
            $scope.aa.x[index].r = null;
            $scope.aa.x[index].text = element.text;  
        });