CODEWITHSUNDEEP
javascriptjasmine
HelloWorld
HelloWorld

Reputation: 11247

Jasmine Create Spy on Native JS Function on Global Window Object

I am writing a test to see if Array.prototype.map was called. I thought this would work since Array.prototype.map is located on the global window object:

    it("does not use Array.prototype.map", function(){

        spyOn(window, "Array.prototype.map")
        fn([2,2,3]);
        expect(Array.prototype.map.calls.count()).toEqual(0);
    });

I receive the error Array.prototype.map does not exist. When I create my own custom global functions, this method works fine. Based on this other post It appears any global functions can be spied on using the syntax I am using above. If I create my own functions, this syntax works. Any ideas on why Array.prototype.map is returning undefined?

Upvotes: 1

Views: 1420

Answers (1)

borbulon
borbulon

Reputation: 1411

hopefully you already got your answer, but for people searching, it's because you should 

spyOn(Array.prototype, 'map');

Upvotes: 3

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