在 Typescript 中构建嵌套的 TreeNode 数组

Question

给定一个 TreeNode 类型的平面一维数组（见下面的接口定义），我想遍历数组并将后续数组元素添加为 children。

递归执行会很棒，我在 non-recursion 的镜头使用了一个缓冲区，但我面临的问题是如何做 node.children[0].children[0]...children[0] 因为注意到只有一个 child 每 parent。

    Childify(results: TreeNode[]): any {
    var node: TreeNode;
    var buffer: TreeNode;
    var count: number = 0;

    for (var res of results) {
        if (count == 0) {
            node = res[0];
            buffer = res[0];
            buffer.children = [];
            node.children = [];
        } else if (count == 1) {
            buffer.children = res[0];
        } else {
            node = buffer;
            node.children = [];
            node.children.push(res[0]);
            buffer = <TreeNode>node.children;
        }

        count++;
    }
}

接口定义：

export interface TreeNode {
label?: string;
data?: any;
icon?: any;
expandedIcon?: any;
collapsedIcon?: any;
children?: TreeNode[];  <---------------
leaf?: boolean;
expanded?: boolean;
type?: string;
parent?: TreeNode;
partialSelected?: boolean;
styleClass?: string;
draggable?: boolean;
droppable?: boolean;
selectable?: boolean;

}

输入：

TreeNode[] = [treeNode1, treeNode2, treeNode3, treeNode4,...,treeNodeX]

输出是一个 TreeNode object，由 children 属性（也是 TreeNode 类型）嵌套：

TreeNode = treeNode1
treeNode1.children = treeNode2
treeNode2.children = treeNode3
treeNode3.children = treeNode4
treeNodeX-1.children = treeNodeX

我不知道如何为X号动态调用treeNode1.children[0].children[0]......children[0]循环中的children，分配给treeNode1中的下一层children。

Answer 1

我已经为你建立了一个算法。我用简单的 javascript 构建了它，但它应该很容易修改以符合您的打字稿界面。

代码在这里：

var flatNodes = [
    {
        name: 'node1',
        children: []
    },
    {
        name: 'node2',
        children: []
    },
    {
        name: 'node3',
        children: []
    },
    {
        name: 'node4',
        children: []
    },
    {
        name: 'node5',
        children: []
    }
];

function linkNodes(flatNodes) {
    flatNodes = flatNodes.slice(); //copy the list

    flatNodes = flatNodes.reverse();

    for (var i = 1; i < flatNodes.length; i++) {
        var previousNode = flatNodes[i - 1];
        var currentNode = flatNodes[i];

        currentNode.children.push(previousNode);
    }

    return flatNodes[flatNodes.length - 1];
}

console.log(linkNodes(flatNodes));

输出在这里：

{
    "name": "node1",
    "children": [
        {
            "name": "node2",
            "children": [
                {
                    "name": "node3",
                    "children": [
                        {
                            "name": "node4",
                            "children": [
                                {
                                    "name": "node5",
                                    "children": []
                                }
                            ]
                        }
                    ]
                }
            ]
        }
    ]
}

Answer 2

我不懂 TypeScript，但在 JavaScript 中我会这样做：

const input = [ new TreeNode("node1")
              , new TreeNode("node2")
              , new TreeNode("node3")
              , new TreeNode("node4")
              , new TreeNode("node5")
              ];

const output = input.reduceRight((child, parent) => {
    parent.children.push(child);
    return parent;
});

console.log(output);

function TreeNode(name) {
    this.name = name;
    this.children = [];
}

希望对您有所帮助。

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