TypeError: Cannot read property '0' of undefined in Angularjs

Question

I saw plenty of questions related to TypeError: Cannot read property '0' of undefined but none of them are helpful to solve my error.

My requirement is onClick button(like: ng-click="addRow(tester.devices)" ) I have to call a function-

In which if already devicelist is present/calling then no need to define _scope.tester.devices = [] otherwise _scope.tester.devices = []; is defined to avoid error: Cannot read property 'unshift' of undefined

My code as follows

_scope.addRow = function (list) {
        _scope.uniqueId = Math.round((Math.random() * 10) * 10000);
        if (_scope.tester.devices) {
            _scope.tester.devices.unshift({
                'name': '',
                'id': '',
                'uniqueId': _scope.uniqueId,
            });


        } else {
            _scope.tester.devices = [];
            _scope.tester.devices.unshift({
                'name': '',
                'id': '',
                'uniqueId': _scope.uniqueId,
            });
        }
        _scope.modifyField[list[0].uniqueId] = true;
    }

Edit1: I defined $scope as _scope. So this is not problem.

This question solved

Answer 1

Pass array to the function, seems like you are passing wrong parameter to the function _scope.addRow()

it worked fine for me after passing array to the function.

Answer 2

I solved this by modifying _scope.modifyField[list[0].uniqueId] = true; to _scope.modifyField[_scope.uniqueId] = true; .

Unfortunately, i unable to delete my question as someone invested time on this as per Stack Overflow rules.

The code as follows:

 _scope.addRow = function (list) {
        _scope.uniqueId = Math.round((Math.random() * 10) * 10000);
        if (_scope.tester.devices) {
            _scope.tester.devices.unshift({
                'name': '',
                'id': '',
                'uniqueId': _scope.uniqueId,
            });
             _scope.modifyField[list[0].uniqueId] = true;

        } else {
            _scope.tester.devices = [];
            _scope.tester.devices.unshift({
                'name': '',
                'id': '',
                'uniqueId': _scope.uniqueId,
            });
        }
        _scope.modifyField[_scope.uniqueId] = true;
    }

Answer 3

Hi, Are you sure your function argument ('list') is an array? It seems undefined.