mixins demonstration in typescript

mixins.ts

function applyMixins(derivedCtor: any, baseCtors: any[]) {
    baseCtors.forEach(baseCtor => {
        Object.getOwnPropertyNames(baseCtor.prototype).forEach(name => {
            derivedCtor.prototype[name] = baseCtor.prototype[name];
        });
    });
}

class ConstructorMixin {
    c: number;

    setC(c: number) {
        this.c = c;
    }
}

class AnotherMethodMixin {
    callMe(): number {
        return 123;
    }
}

class First implements ConstructorMixin, AnotherMethodMixin {
    a: number;
    b: number;
    c: number;

    setC: (c: number) => void;
    callMe: () => number;

    constructor() {
        this.a = 1;
        this.b = 2;
        this.setC(3);
    }
}
applyMixins(First, [ConstructorMixin, AnotherMethodMixin]);

ddescribe('test mixins', () => {
    it('', () => {
        var f = new First();
        expect(f.a).toBe(1);
        expect(f.b).toBe(2);
        expect(f.c).toBe(3);
        expect(f.callMe()).toBe(123);
    });
});