JavaScript output spiral matrix implementation method

(function() {
  var map = (function() {
    function map(n) {
      this.map = [], this.row = 0, this.col = -1, this.dir = 0, this.n = n;
      // 建立个二维数组
      for (var i = 0; i < this.n; i++) { this.map.push([]); }
      // 定义移动的顺序为 右，下，左，上
      var order = [this.right, this.bottom, this.left, this.up];
      i = 0;
      do {
        // 能移动则更新数字，否则更改方向
        order[this.dir % 4].call(this) ? i++ : this.dir++;
        // 赋值
        this.map[this.row][this.col] = i;
      } while (i < n * n);
    }
    map.prototype = {
      print: function() { for (var i = 0; i < this.n; i++) { console.log(this.map[i].join(&#39; &#39;)) } },
      // 向该方向移动
      left: function() { return this.move(this.row, this.col - 1); },
      right: function() { return this.move(this.row, this.col + 1); },
      up: function() { return this.move(this.row - 1, this.col); },
      bottom: function() { return this.move(this.row + 1, this.col); },
      // 如果坐标在范围内，并且目标没有值，条件满足则更新坐标
      move: function(row, col) {
        return (0 <= row && row < this.n) && (0 <= col && col < this.n) && !this.map[row][col] && (this.row = row, this.col = col, true);
      },
    };
    return map;
  })();
  new map(6).print();
})();