将 ruby​​ 方法移植到 javascript

Question

我正在尝试将一些 ruby​​ 代码移植到 javascript，但我正在为某一行苦苦挣扎

Ruby 代码如下： 它会从俄罗斯方块游戏中删除所有完整的行：

  # 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是一个二维数组，初始化如下：

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

到目前为止我所做的javascript如下

我已经在评论中指出这是我无法解决的问题

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;
                }
            }
        }

任何想法如何移植有问题的线路？

Answer 1

如果我理解正确，您希望将数组放在给定位置并将其复制到一个位置。

你可以这样做：

  this.grid[this.grid.length - k + 1] =  this.grid[this.grid.length - k].slice(0);

Answer 2

TL;DR @raam86 给出了正确答案。不同之处在于，在 ruby​​ 中 Array.new old_arr 将创建数组的副本。在 JS 中，您可以通过 old_arr.slice() 实现相同的目标

据我了解，您的 sn-p 可以变成这样：

function falsy(val) {
  return undefined === val || null === val || false === val;
}

function all(arr) {
  return arr.reduce(function (a, b) { return a && !falsy(b); }, true);
}

// 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.
function removeFilled() {
  var i, j, k, rects,
      _grid       = this.grid,
      _numColumns = this.numColumns,
      _blockSize  = this.blockSize;

  for (i = 2; i < _grid.length; i++) {
    // see if this row is full (has no nil)
    if (all(_grid[i])) {
      // remove from canvas blocks in full row
      for (j = 0; j < _numColumns; j++) {
        _grid[i][j].remove();
        _grid[i][j] = undefined;
      }

      // move down all rows above and move their blocks on the canvas
      for (j = _grid.length - i + 1; j < _grid.length; j++) {
        rects = _grid[_grid.length - j];
        for (k = 0; k < rects.length; k++) {
          if (!falsy(rects[k])) {
            rects[k].move(0, _blockSize);
          }
        }

        _grid[_grid.length - j + 1] = _grid[_grid.length - j].slice();
      }

      _grid[0] = new Array(_numColumns);
      this.score += 10;
    }
  }

  return this;
}

PS 你真的应该检查你正在使用的逻辑并考虑重构它。例如，在一个地方你使用num_columns 在另一个地方你传递行的元素数量。你迭代数组改变它，我建议你考虑操作数组的副本，在这种情况下你的代码会变得不那么复杂。