explain the order in which beforeEach gets called in Jasmine and the test variables scope

jasmine-before-each-call-order

describe("jasmine class variables", function() {
    var foo = 0;

    beforeEach(function() {
        foo += 1;
    });

    it("can be assigned in the before each", function() {
        expect(foo).toEqual(1);
    });

    it("but the class does not get recreated for each it, so remember to cleanup", function() {
        expect(foo).toEqual(2);
    });

    it("since this is the first describe level foo only gets incremented in one", function() {
        expect(foo).toEqual(3);
    });

    describe("nested describe", function() {
        var bar = 0;

        beforeEach(function() {
            bar = 1;
        });

        afterEach(function(){
            bar = 0;
        });

        it ("can reference parent scope", function(){
            expect(foo).toEqual(4);
        });

        it("class variables", function() {
            expect(bar).toBe(1);
        });

        it("must be reset in the afterEach", function() {
            expect(bar).toBe(1);
        });

        it ("in the meantime parent scope beforeEach got called", function(){
            expect(foo).toEqual(7);
        });
    });

    describe("second level desccibe foo gets incremented in two", function(){
        beforeEach(function(){
            foo += 1;
        });

        it("describes get called a lot", function() {
            expect(foo).toBe(9);
        });

        it("foreach it all of its parents describes get called", function() {
            expect(foo).toBe(11);
        });
    });
});