我如何修复这个在JavaScript中完成的对象的“引用网格”？

Question

我试图在JavaScript中建立一个3x3的“块”对象网格，每个网格都通过4个方向参数“下面”、“左”、“上面”和“右”包含对它旁边的块的引用。问题是由于JavaScript对象构造的性质，我在要定义的第一个块中得到了许多未定义的“块”引用。

下面是我正在努力实现的目标的可视化：

    [00][01][02]
    [10][11][12]
    [20][21][22]

这是我的代码：

    // Block variable declarations

    var block00;
    var block01;
    var block02;

    var block10;
    var block11;
    var block12;

    var block20;
    var block21;
    var block22;

    // Block object constructor

    function block(below, left, above, right){
        this.below = below;
        this.left = left;
        this.above = above;
        this.right = right;
    }

    // Row 1

    block00 = new block(block10, null, null, block01);
    block01 = new block(block11, block00, null, block02);
    block02 = new block(block12, block01, null, null);

    // Row 2

    block10 = new block(block20, null, block00, block11);
    block11 = new block(block21, block10, block01, block12);
    block12 = new block(block22, block11, block02, null);

    // Row 3

    block20 = new block(null, null, block10, block21);
    block21 = new block(null, block20, block11, block22;
    block22 = new block(null, block21, block12, null);

所以，例如，打电话

    block00.below

将返回一个未定义的值，但我希望它返回block10。

谢谢!

Answer 1

在将引用分配给对象之前，您需要构造它们。那是没有办法的。

这样做的一个简单方法是从构造函数中移除below和right参数，并在构造该块时动态设置这些字段：

function block(left, above) {
    this.below = null;
    this.left = left;
    this.above = above;
    this.right = null;

    if (left) left.right = this;
    if (above) above.below = this;
}