Object Equality in Typescript

I'm creating a lib on vectors in typescript. My very first test failed:).

It's related to object equality in TypeScript/JavaScript but I can't find a way to make the test green. No object equality is mentioned in typescript's official doc http://www.typescriptlang.org/Handbook#classes.

Could someone please give me a hand ?

This is the source code.

class Vector {
    x: number;
    y: number;

    constructor(x: number, y: number) {
        this.x = x;
        this.y = y;
    }

    add(that: Vector) {
        return new Vector(this.x + that.x, this.y + that.y);
    }
}

export = Vector;

Then I have a unit test on this class as follows

 var Vector = require("../lib/vector")

 describe("vector", function () {
  it("should add another vector", function () {
    var v1 = new Vector(1, 1);
    var v2 = new Vector(2, 3);
    expect(v1.add(v2)).toEqual(new Vector(3, 4));
  });
});

When executed obtains the following error

Failures: 
1) vector should add another vector
1.1) Expected Vector({ x: 3, y: 4 }) to be Vector({ x: 3, y: 4 }).