Pull-based Async Objects -- Demo

Car.js

//1 dimentional, constant speed car

//private
function _Car (vision, address, speed, id) {
  this.visual = {id: id, brake_light: false, address: address, _speed: speed + "mph", _car: this};
  this._vision = vision;
  this._speed = speed;
  
  this._brake = function () {
    this.visual.brake_light = true;
  };
  this._accelerate = function () {
    this.visual.brake_light = false;
    this.visual.address ++;
  };
  this._too_close = function (carsp) {
    var diff = carsp.address - this.visual.address;
    return diff < 30 && diff > 0;
  };
  this._ai = function () {
    var self = this;
    setInterval(function () {
      var close_cars = self._vision;  //cars in front
      if (close_cars.some(function (carsp) { return carsp.brake_light; }))  //see break light
        self._brake();
      else if (close_cars.filter(self._too_close.bind(self)).length)  //really close
        self._brake();
      else self._accelerate();
    }, 3600 / (speed * 100) * 100);
  };
  
  this._ai();
}


//public
//vision :: [CarVisual]
//address :: Int
//speed  :: Int  -- miles/hour
//id     :: String
function CarVisual (vision, address, speed, id) {
  return new _Car(vision, address, speed, id).visual;
}

Road.js

//cars :: [CarVisual]
function Road (cars) {
  this.cars = cars;
  
  this._init = function () { console.log("init road");
    var self = this;
    function car_address (car) { return car.address; }
    setInterval(function () {
      var cars = _.sortBy(self.cars, function (c) { return - c.address; });
      for (var i in cars) {
        for (var j in cars) {
          if (i == j) continue;
          var car_infront = _.max([cars[i], cars[j]], car_address);
          var car_rear = _.min([cars[i], cars[j]], car_address);
          var distance = car_infront.address - car_rear.address;
          if (distance < 100 && distance > 0)
            car_rear._car._vision.unshift(car_infront);
          else {
            car_rear._car._vision = _.without(car_rear.vision, car_infront);
          }
        }
      }
    }, 1000);
  };

  this._init();
}

run.js

new Road([
  new CarVisual([], 300, 125, "A"),
  new CarVisual([], 270, 70, "B"),
  new CarVisual([], 200, 80, "C"),
  new CarVisual([], 100, 100, "D")
]);