In Jasmine, array.includes does not work (must be replaced by other functions). Why?

Question

My problem seems very strange. I have a constructor with a new, very simple function, that should check if a variable is contained in an array. It works perfectly (i use this function in a form).

But... i cannot write any Unit Test on this function, since Karma/Jasmine cannot see the function "includes" of the array.

Could somebody suggest me what to do? Here the situation, a little bit simplified:

//theConstructor to be tested

    vm.isNameAlreadyUsed = function () {
    //debut logging:
        console.log ("vm.allNames ",vm.allNames);  // output: vm.allNames ['A', 'B', 'C']
        console.log ("and vm.nameToBeChecked is ",vm.nameToBeChecked);    //output: and vm.nameToBeChecked is 'A'

        return vm.allNames.includes(vm.nameToBeChecked);
        // The previous works as expected at runtime, but it causes the following exception in karma/jasmine:
        // TypeError: undefined is not a constructor (evaluating 'vm.allNames.includes(vm.nameToBeChecked)
    };

//Test (karma/jasmine)

        theConstructor.allNames = ["A", "B", "C"];
        theConstructor.nameToBeChecked = "A";
        var result theConstructor.isNameAlreadyUsed();           //error!
        expect(result).toBeTruthy();

Is it possible that jasmine cannot see "includes"? the array is filled, the variable also... and why should be any constructor there?

TypeError: undefined is not a constructor (evaluating 'vm.allNames.includes(vm.nameToBeChecked)

Thanks

---

UPDATE

I noticed that in jasmine, any call to "includes" causes an error. It doesn't depends where. Example it's enough to write the following code in a jasmine file to get an error mentioning a... constructor (?!?):

[1, 2, 3].includes(2);
// TypeError: undefined is not a constructor (evaluating '[1, 2, 3].includes(2)') in  ...

Answer 1

I would guess this is most likely due to one of two things:

1. Your node version could be < 6.0.0, since Array.prototype.includes is not supported natively until [email protected], or

2. The browser in your karma config file is set to "IE", since Internet Explorer does not support Array.prototype.includes.