树结构未按预期构建

Question

我正在尝试编写一个函数来从给定的起始目录创建树。换句话说，我选择一个目录，然后该函数绝对映射该特定目录中的所有内容。我以前从未做过这样的事情，但我接近预期的输出。但是，我不确定我哪里出错了。

起始目录

> Test Root
    > 1a
    > 1b
        > 2a
        > 2b
        > 2c
    > 1c
        > 2a
    > 1d
        > 2a
        > 2b
    > testfile.txt

输出

第一关很好。第二层几乎可以使用了，但由于某种原因，它复制了 parent 属性并创建了一个额外的嵌套对象。它还总是插入 type 属性。我试过删除 constructor 中的属性，但输出同样令人困惑。

{
  "parent": null,
  "path": "C:\Users\Anthony\Desktop\Test Root",
  "name": "Test Root",
  "kids": [
    {
      "parent": {
        "parent": "C:\Users\Anthony\Desktop\Test Root",
        "path": "C:\Users\Anthony\Desktop\Test Root\1a",
        "name": "1a",
        "kids": []
      },
      "type": "fileType"
    },
    {
      "parent": {
        "parent": "C:\Users\Anthony\Desktop\Test Root",
        "path": "C:\Users\Anthony\Desktop\Test Root\1b",
        "name": "1b",
        "kids": [
          {
            "parent": {
              "parent": "C:\Users\Anthony\Desktop\Test Root\1b",
              "path": "C:\Users\Anthony\Desktop\Test Root\1b\2a",
              "name": "2a",
              "kids": []
            },
            "type": "fileType"
          },
          {
            "parent": {
              "parent": "C:\Users\Anthony\Desktop\Test Root\1b",
              "path": "C:\Users\Anthony\Desktop\Test Root\1b\2b",
              "name": "2b",
              "kids": []
            },
            "type": "fileType"
          },
          {
            "parent": {
              "parent": "C:\Users\Anthony\Desktop\Test Root\1b",
              "path": "C:\Users\Anthony\Desktop\Test Root\1b\2c",
              "name": "2c",
              "kids": []
            },
            "type": "fileType"
          }
        ]
      },
      "type": "fileType"
    },
    {
      "parent": {
        "parent": "C:\Users\Anthony\Desktop\Test Root",
        "path": "C:\Users\Anthony\Desktop\Test Root\1c",
        "name": "1c",
        "kids": [
          {
            "parent": {
              "parent": "C:\Users\Anthony\Desktop\Test Root\1c",
              "path": "C:\Users\Anthony\Desktop\Test Root\1c\2a",
              "name": "2a",
              "kids": []
            },
            "type": "fileType"
          }
        ]
      },
      "type": "fileType"
    },
    {
      "parent": {
        "parent": "C:\Users\Anthony\Desktop\Test Root",
        "path": "C:\Users\Anthony\Desktop\Test Root\1d",
        "name": "1d",
        "kids": [
          {
            "parent": {
              "parent": "C:\Users\Anthony\Desktop\Test Root\1d",
              "path": "C:\Users\Anthony\Desktop\Test Root\1d\2a",
              "name": "2a",
              "kids": []
            },
            "type": "fileType"
          },
          {
            "parent": {
              "parent": "C:\Users\Anthony\Desktop\Test Root\1d",
              "path": "C:\Users\Anthony\Desktop\Test Root\1d\2b",
              "name": "2b",
              "kids": []
            },
            "type": "fileType"
          }
        ]
      },
      "type": "fileType"
    },
    {
      "parent": {
        "parent": "C:\Users\Anthony\Desktop\Test Root",
        "path": "C:\Users\Anthony\Desktop\Test Root\testfile.txt",
        "name": "testfile.txt",
        "type": "fileType"
      },
      "type": "fileType"
    }
  ]
}

函数

async function createTree(root){
  const
    Node = class {
      constructor(parent, path, name, fifo){
        this.parent = parent
        this.path = path
        this.name = name
        fifo ? this.kids = [] : this.type = 'fileType'
      }
      addChild(parent, path, name, fifo){
        this.kids.push(new Node(parent, path, name, fifo))
      }
    },
    traverse = async function(node, path){
      const childPaths = await fsp.readdir(path)
      for (const childPath of childPaths){
        const
          name = childPath,
          stats = await fsp.stat(join(path, childPath))
        let
          fifo

        if (stats.isDirectory()) fifo = 1
        else if (stats.isFile()) fifo = 0

        const
          childNode = new Node(path, join(path, childPath), name, fifo)

        node.addChild(childNode)

        traverse(childNode, join(path, childPath))
      }
    },
    rootName = root.slice(-1) === '\' ? root.slice(0,1) : root.slice(root.lastIndexOf('\')+1),
    tree = new Node(null, root, rootName, 1)

    traverse(tree, root)

    setTimeout(function(){
      console.log(JSON.stringify(tree, null, 2))
    }, 2500)
}

我刚刚意识到我的异步函数没有返回任何东西。明天我将不得不检查所有这些。

Answer 1

问题是您在这里只将第一个参数传递给 addChild 函数。

addChild 函数需要提供 4 个参数。然而：

node.addChild(childNode)

// is approximately equivalent to:

addChild ( Node {...}, undefined, undefined, undefined)

你应该这样调用函数：

node.addChild(childNode.path, childNode.path, childNode.name, childNode.fifo)

你在逻辑上走在正确的道路上，接近一个很好的递归解决方案，但我认为 class 有点矫枉过正，对于像这样的功能性问题来说太面向对象了。这是一个功能更强大的版本的快速示例，它应该会给您预期的结果：

const nodePath = require('path');
const fs = require('fs');

/**
 * Supply an `fs` function and it will turn it into a promisified version
 * @param {Function} fn The function to promisify. This means you do not 
 * need the `fsp` library.
 */
function promisify (fn) {
  return (...args) => new Promise((resolve, reject) => fn(...args, (err, data) => err ? reject(err) : resolve(data)));
};

// Create promisified versions of `fs.stat` and `fs.readdir`
const stat = promisify(fs.stat);
const readdir = promisify(fs.readdir);

function createDirectory (parent, path, name, kids) {
  return { parent, path, name, kids: kids || [] };
};

function createFile (parent, path, name) {
  return { parent, path, name, type: 'fileType' };
}

// The main recursive function.
async function createTree (parent, path) {
  let stats = await stat(path);

  if (stats.isDirectory()) {
    const children = await readdir(path);

    // Because each recursive call retruns a promise, we want to continue only when
    // all of them have resolved. So we use Promise.all for this.
    let child_nodes = await Promise.all(
      children.map(child => createTree(path, nodePath.join(path, child)))
    );

    // Create a directory node
    return createDirectory(parent, path, nodePath.basename(path), child_nodes);
  }

  // Create a file node
  return createFile(parent, path, nodePath.basename(path));
};


// Startup code, can use your own stuff here.
async function start () {
  let tree = await createTree(null, '/home/james/Whosebug/58706769/Test Root');

  console.log(JSON.stringify(tree, null, 2));
}

start();

运行这个文件在 Node 中，我得到以下输出：

{
  "parent": null,
  "path": "/home/james/Whosebug/58706769/Test Root",
  "name": "Test Root",
  "kids": [
    {
      "parent": "/home/james/Whosebug/58706769/Test Root",
      "path": "/home/james/Whosebug/58706769/Test Root/1a",
      "name": "1a",
      "kids": []
    },
    {
      "parent": "/home/james/Whosebug/58706769/Test Root",
      "path": "/home/james/Whosebug/58706769/Test Root/1b",
      "name": "1b",
      "kids": [
        {
          "parent": "/home/james/Whosebug/58706769/Test Root/1b",
          "path": "/home/james/Whosebug/58706769/Test Root/1b/2a",
          "name": "2a",
          "kids": []
        },
        {
          "parent": "/home/james/Whosebug/58706769/Test Root/1b",
          "path": "/home/james/Whosebug/58706769/Test Root/1b/2b",
          "name": "2b",
          "kids": []
        },
        {
          "parent": "/home/james/Whosebug/58706769/Test Root/1b",
          "path": "/home/james/Whosebug/58706769/Test Root/1b/2c",
          "name": "2c",
          "kids": []
        }
      ]
    },
    {
      "parent": "/home/james/Whosebug/58706769/Test Root",
      "path": "/home/james/Whosebug/58706769/Test Root/1c",
      "name": "1c",
      "kids": [
        {
          "parent": "/home/james/Whosebug/58706769/Test Root/1c",
          "path": "/home/james/Whosebug/58706769/Test Root/1c/2a",
          "name": "2a",
          "kids": []
        }
      ]
    },
    {
      "parent": "/home/james/Whosebug/58706769/Test Root",
      "path": "/home/james/Whosebug/58706769/Test Root/1d",
      "name": "1d",
      "kids": [
        {
          "parent": "/home/james/Whosebug/58706769/Test Root/1d",
          "path": "/home/james/Whosebug/58706769/Test Root/1d/2a",
          "name": "2a",
          "kids": []
        },
        {
          "parent": "/home/james/Whosebug/58706769/Test Root/1d",
          "path": "/home/james/Whosebug/58706769/Test Root/1d/2b",
          "name": "2b",
          "kids": []
        }
      ]
    },
    {
      "parent": "/home/james/Whosebug/58706769/Test Root",
      "path": "/home/james/Whosebug/58706769/Test Root/testfile.txt",
      "name": "testfile.txt",
      "type": "fileType"
    }
  ]
}

树结构未按预期构建

Tree structure not building as expected

javascript

tree

fs

node.js

data-structures

起始目录

输出

函数