Create nested object of file paths

Question

I'm walking large directory tree recursively (from 100,000 to 1,000,000 objects) and need to add each file or directory to deeply nested object.

Let's assume I got file paths like

/path/to/file1
/path/to/file2
...
/pathX/file1000000

and I need to create following nested object based on them:

{
  "name": "/",
  "value": 300,
  "children": [
    { 
       "name": "/pathX",
       "value": 100,
       "children": [
       {
         "name": "/pathX/file1000000",
         "value": 100
       }
    },
    {
      "name": "/path",
      "value": 200,
      "children": [
        {
          "name": "/path/to",
          "value": 200,
          "children": [
            {
              "name": "/path/to/file1",
              "value": 100
            },

            {
              "name": "/path/to/file2",
              "value": 100
            }
          ]
        }
      ]
    }
  ]
}

The value is a file size or sum of nested file sizes. To keep things simple, let's assume its equal to 100 for file1, file2 and fileN.

I was able to build nested object for one file, but having issues with building it for many files with different paths:

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

let file = '/opt/bin/file1'
let size
fs.stat(file, (err, stats) => { size = stats.size })
let paths = file.split(path.sep)

let nameChild = file
let objChild = { "name" : nameChild, "value" : size }
let nameParent
let objParent

for (var i in paths) {

    if (i==0) continue

    nameParent = path.dirname(nameChild)

    objParent = { "name" : nameParent, "value" : size, "children" : [ objChild ] }

    nameChild = nameParent
    objChild = objParent

}

console.log(JSON.stringify(objParent))

Moritz Roessler · Accepted Answer · 2018-01-28 15:25:18Z

2

There you go :)

function buildTree(pathes, getValueCB) {

  var currentPath, lastPath, node, parent, map = {
      "": {
        children: []
      }
    },
    stack = [""]

  for (let path of pathes) {
    let nodes = path.split("/");
    for (let i = 0; i < nodes.length; i++) {
      currentPath = "/" + nodes.slice(1, i + 1).join("/")
      lastPath = stack[stack.length - 1]
      parent = map[lastPath]
      if (!map[currentPath]) {
        node = {
          name: currentPath,
          value: getValueCB(currentPath),
          children: []
        }
        parent.children.push(node);
        map[currentPath] = node;
      }
      stack.push(currentPath)
    }
    stack = stack.slice(0, 1)
  }
  return map[""].children[0];
}

function getFileSizeSync() {
  return 200
}
var tree = buildTree(["/path/to/file1", "/path/to/file2"], function(path) {
  return getFileSizeSync(path)
})

console.log (tree)

Here's the updated version that calculates the size recursively. (I can't put it into a snippet, that's why i leave the old one)

var fs = require('fs')
var Path = require ('path')

function calcSize (node) {
    var children = node.children; 
    node.value = children.reduce (function (size, child) {
        return size + child.value || reduceSize (child);
    }, 0)
    return node.value;
}
function getFileSizeSync(path) {
  var size = fs.statSync(path).size
  return size
}

function buildTree(pathes, getValueCB) {

  var currentPath, lastPath, node, parent, map = {
      "": {
        children: []
      }
    },
    stack = [""]

  for (let path of pathes) {
    let nodes = path.split(Path.sep);
    for (let i = 0; i < nodes.length; i++) {
      currentPath = Path.sep + nodes.slice(1, i + 1).join(Path.sep)
      lastPath = stack[stack.length - 1]
      parent = map[lastPath]
      if (!map[currentPath]) {
        node = {
          name: currentPath,
          value: getFileSizeSync(currentPath),
          children: []
        }
        parent.children.push(node);
        map[currentPath] = node;
      }
      stack.push(currentPath)
    }
    stack = stack.slice(0, 1)
  }
  calcSize (map[""])
  return map[""].children[0];
}


var tree = buildTree(["/path/to/file1", "/path/to/file2"])

console.log (tree)

edited Jan 28, 2018 at 15:25

answered Jan 28, 2018 at 13:37

Moritz Roessler

8,67329 silver badges57 bronze badges

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3 Comments

Jamiec Over a year ago

I think you're missing the point that the parent directories should sum the file sizes within for their values

Moritz Roessler Over a year ago

@Jamiec Indeed! Fixed it

Moritz Roessler Over a year ago

@SystemsRebooter I added that part as well

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