JS solution to part of robot

gistfile1.txt

_ = require('./underscore');

Robot = function () {
  var directions = {
    north: [0, 1],
  	east:  [1, 0],
  	south: [0, -1],
  	west:  [-1, 0]
  }

	function directionNames() {
		return Object.keys(directions)
	}

	this.bearing = function() {
		return directionNames()[this._bearing]
	};

	this.orient = function (direction) {
		if (_.contains(directionNames(), direction)){
			this._bearing = directionNames().indexOf(direction)
		} else {
			throw "Invalid Robot Bearing";
		};
	};

	this.turnRight = function() {
		this.turn(1)
	};

	this.turnLeft = function() {
	  this.turn(-1)
	};

  this.at = function(x, y) {
  	this._at = [x,y]
  }

  this.coordinates = function() {
  	return this._at
  }

  this.advance = function() {
  	var delta = directions[this.bearing()]

    this._at = _.zip(this._at, delta).map(function(diff) {
    	return diff.reduce(function(a, b) { return a + b })
    })
  }

  // (map sumDiff) . zip $ _at delta

	this.turn = function(direction) {
		var len = directionNames().length
		this._bearing = (this._bearing + direction + len) % len
	}
};

Simulator = function () {

};