AngularJS throwing error when getting length of empty input

Question

I am currently trying to validate a card with AngularJS. This works fine until the user deletes all the inputted data from the input field, then it throws the following errors:

angular.js:11004 undefined is not an object (evaluating '$scope.card.length')

My HTML Code:

<input type="text" class='form-control' id='card' ng-model="card" ng-change="validateCard()" required>

JavaScript code that throws the error when the input is empty:

$scope.validateCard = function() {
    // Get card type
    if ($scope.card.length) { // <-- throws the error
        [...]

I also tried

if ($scope.card.length !== undefined) {

but it didn't help.

$scope.card might as well be undefined. if($scope.card && $scope.card.length) maybe? — tanmay
– tanmay, Commented Apr 11, 2017 at 9:08

Muhammed Neswine · Accepted Answer · 2017-04-11 09:08:41Z

2

Thats because you cannot take length of undefined value. You could use something like this:

if ($scope.card && $scope.card.length) { }

answered Apr 11, 2017 at 9:08

Muhammed Neswine

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Comments

Sajeetharan · Accepted Answer · 2017-04-11 09:12:15Z

0

You can check for both using && condition

$scope.validateCard = function() {
   if ($scope.card && $scope.card.length) { 
}

answered Apr 11, 2017 at 9:12

Sajeetharan

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Comments

Groben · Accepted Answer · 2017-04-11 09:17:21Z

0

Just check that your item is defined:

if (angular.isDefined($scope.card) && $scope.card.length) { }

answered Apr 11, 2017 at 9:17

Groben

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