javascript singleton

test_singleton.js

describe('decorator', function() {
  // body...
  it('singleton1', function(done) {
    var Car = function(){
        var instance = this;
        this.a  = 100;
        Car = function(){
            return instance;
        };
    };

    var car1 = new Car();
    var car2 = new Car();
    var car3 = new Car();
    expect(car1).toBe(car2);
    expect(car1).toBe(car3);
    expect(car2).toBe(car3);
  });

  it('singleton2', function(done) {
    var Car = function(){
        var instance;

        Car = function(){
            return instance;
        };

        Car.prototype = this;

        instance = new Car();
        return instance;
    };
    var car1 = new Car();
    var car2 = new Car();
    var car3 = new Car();
    expect(car1).toBe(car2);
    expect(car1).toBe(car3);
    expect(car2).toBe(car3);
  });
});