Power of Thor - Episode 1

/**
 * Auto-generated code below aims at helping you parse
 * the standard input according to the problem statement.
 * ---
 * Hint: You can use the debug stream to print initialTX and initialTY, if Thor seems not follow your orders.
 **/

var inputs = readline().split(' ');
var lightX = parseInt(inputs[0]); // the X position of the light of power
var lightY = parseInt(inputs[1]); // the Y position of the light of power
var initialTX = parseInt(inputs[2]); // Thor's starting X position
var initialTY = parseInt(inputs[3]); // Thor's starting Y position

var Position = function(x, y) {
    this.x = x;
    this.y = y;
};

Position.prototype.add = function(pos) {
  this.x += pos.x;
  this.y += pos.y;
  return this;
};

Position.prototype.substract = function(pos) {
  this.x -= pos.x;
  this.y -= pos.y;
  return this;
};

Position.prototype.compare = function(pos) {
  return this.x === pos.x && this.y === pos.y;  
};

var direction = {
    x: {
        '1': 'E',
        '-1': 'W',
    },
    y: {
        '-1': 'N', 
        '1': 'S',
    },
};

var Thor = function(pos) {
  this.position = pos;  
};

Thor.prototype.move = function(vector) {
  this.position.x += vector.x;
  this.position.y += vector.y;
  print((direction.y[vector.y] || "").concat(direction.x[vector.x] || ""));
};

var ai = new Thor(new Position(initialTX, initialTY));
var light = new Position(lightX, lightY);

// game loop
while (true) {
    var remainingTurns = parseInt(readline());
    var axis = new Position(lightX, lightY).substract(new Position(ai.position.x, ai.position.y));
    var vector = new Position(Math.sign(axis.x), Math.sign(axis.y));
    printErr(vector.x)
    ai.move(vector);
}