将ruby方法移植到javascript

我正试图将一些ruby代码移植到javascript，但有一行很吃力

Ruby代码如下：它删除了俄罗斯方块游戏中的所有完整行：

  # removes all filled rows and replaces them with empty ones, dropping all rows
  # above them down each time a row is removed and increasing the score.  
  def remove_filled
    (2..(@grid.size-1)).each{|num| row = @grid.slice(num);
      # see if this row is full (has no nil)
      if @grid[num].all?
        # remove from canvas blocks in full row
        (0..(num_columns-1)).each{|index|
          @grid[num][index].remove;
          @grid[num][index] = nil
        }
        # move down all rows above and move their blocks on the canvas
        ((@grid.size - num + 1)..(@grid.size)).each{|num2|
          @grid[@grid.size - num2].each{|rect| rect && rect.move(0, block_size)};
          # I can't port this line
          @grid[@grid.size-num2+1] = Array.new(@grid[@grid.size - num2])
        }
        # insert new blank row at top
        @grid[0] = Array.new(num_columns);
        # adjust score for full flow
        @score += 10;
      end
    }
    self
  end

其中@grid是二维数组，初始化如下：

@grid = Array.new(num_rows) {Array.new(num_columns)}

到目前为止，我所做的javascript低于

我在评论中注意到，这是我无法计算的行

removeFilled() {
            for (var i = 2; i < this.grid.length; i++) {
                var row = this.grid.slice(i);
                var allFull = true;
                for (var g = 0; g < this.grid[i].length; g++ ) {
                    if (this.grid[i][g] == undefined) {
                        allFull = false;
                        break;
                    }
                }
                if (allFull) {
                    for (var j = 0; j < this.numColumns; j++) {
                        this.grid[i][j].remove();
                        this.grid[i][j] = undefined;
                    }
                    for (var k = this.grid.length - i + 1; k <= this.grid.length; k++) {
                        var rects = this.grid[this.grid.length - k];
                        for(var l = 0; l < rects.length; l++) {
                            var rect  = rects[l];
                            if (rect) {
                                rect.move(0, this.blockSize);
                            }
                        }
                        // ***this is the line I can't port
                        this.grid[this.grid.length - k + 1] = new Array(this.grid[this.grid.length - k]);
                    }
                    this.grid[0] =  new Array(this.numColumns);
                    this.score += 10;
                }
            }
        }

有什么想法吗？