Jasmine 2.0 SO answer

Jasmine 2.0 adding custom matchers

HTML

<script src="http://jasmine.github.io/2.0/lib/jasmine.js"></script>
<script src="http://jasmine.github.io/2.0/lib/jasmine-html.js"></script>
<script src="http://jasmine.github.io/2.0/lib/boot.js"></script>
<link rel="stylesheet" href="http://jasmine.github.io/2.0/lib/jasmine.css">

JavaScript

function gimmeANumber() {
    var x = 4;
    return x;
}

describe('Hello world', function () {

    beforeEach(function () {
        jasmine.addMatchers({
            toBeDivisibleByTwo: function () {
                return {
                    compare: function (actual, expected) {
                        return {
                            pass: (actual % 2) === 0
                            
                        };
                    }
                };
            }
        });
    });

    it('is divisible by 2', function () {
        expect(gimmeANumber()).toBeDivisibleByTwo();
        expect(5).not.toBeDivisibleByTwo();
    });

});