Can't understand why an array is empty in Jasmine test

Question

I'm trying to test a simple function (cloning an array) to learn how Jasmine works. The function I'm testing works (or not, it doesn't matter). But I don't know how to test it right. This is the suite I've created:

describe("Clone an array of arrays", function(){

    var array_element;
    var array_origin;
    var array_cloned;

    beforeEach(function() {
        array_element = [4,0];
        array_origin = [1,2,array_element];
        array_cloned= array_Clone(array_origin);
    });

    it("Clone the array", function() {
        expect(array_cloned).toEqual(array_origin);
    });

    /* Commented because it is not relevant for the question
    // We should clone, not copy references, to subarrays
    if("Clone the elements", function(){
        expect(array_cloned[2]).not.toBe(array_element);
    });
    */
})

But, when I run it, I get the following error on the first test:

Expected [ 1, 2, [ 4, 0 ] ] to equal [  ].

Why array_origin is an empty array? I've been looking for information about this, but I can't understand why it doesn't have the value initialized at beforeEach() ([1,2,[3,4]);

What is the correct way to test this?

Answer 1

Replace this:

array_origin = [1,2,array_element]; // this will just put an array into an array
array_cloned= array_Clone(array_origin);

with this:

array_origin = [1,2].concat(array_element);
array_cloned = array_origin.map(function(elem) { return elem; }); // This is not a deep copy!