Node Challenge, make this work by changing use

nodechallenge.js

var Instance = function (options) {
  this.options = options;
};

Instance.prototype.use = function (fn) {
  var self = this;
  process.nextTick(() => {
    fn.call(self, self.options);
  })
  return this;
};

function foo (options) {
  console.assert(options.foo.x === 1);
  setImmediate(() => {
    this.options.bar.y = 3;
  })
}

function bar (options) {
  console.assert(options.bar.y === 3, 'bar options invalid: ' + options.bar.y);
}

var instance = new Instance({ foo: { x: 1 }, bar: { x: 2 } })
instance.use(foo).use(bar)