I have an array of objects that looks like this:

[{ name: 'test',
  size: 0,
  type: 'directory',
  path: '/storage/test' },
{ name: 'asdf',
  size: 170,
  type: 'directory',
  path: '/storage/test/asdf' },
{ name: '2.txt',
  size: 0,
  type: 'file',
  path: '/storage/test/asdf/2.txt' }]

There could be any number of arbitrary path's, this is the result of iterating through files and folders within a directory.

What I'm trying to do is determine the 'root' node of these. Ultimately, this will be stored in mongodb and use materialized path to determine it's relationships.

In this example, /storage/test is a root with no parent. /storage/test/asdf has the parent of /storage/test which is the parent to /storage/test/asdf/2.txt.

My question is, how would you go about iterating through this array, to determine the parent's and associated children? Any help in the right direction would be great!

Thank you

I have an array of objects that looks like this:

[{ name: 'test',
  size: 0,
  type: 'directory',
  path: '/storage/test' },
{ name: 'asdf',
  size: 170,
  type: 'directory',
  path: '/storage/test/asdf' },
{ name: '2.txt',
  size: 0,
  type: 'file',
  path: '/storage/test/asdf/2.txt' }]

There could be any number of arbitrary path's, this is the result of iterating through files and folders within a directory.

What I'm trying to do is determine the 'root' node of these. Ultimately, this will be stored in mongodb and use materialized path to determine it's relationships.

In this example, /storage/test is a root with no parent. /storage/test/asdf has the parent of /storage/test which is the parent to /storage/test/asdf/2.txt.

My question is, how would you go about iterating through this array, to determine the parent's and associated children? Any help in the right direction would be great!

Thank you

• javascript
• node.js
• tree

• Are you looking for something that'll actually give you a directory tree like structure, where /storage/test belongs to the implied node /storage which in turn would belong to the implied root /? Not entirely sure what kind of data structure you want to end up with. – Marcus Stade Commented Oct 23, 2013 at 2:16
• To clarify my comment, what if you have a file at /storage/test and one at /storage/text/asdf/2.txt then /storage/text/asdf would have to be implied unless parent could also mean grandparent. – Marcus Stade Commented Oct 23, 2013 at 2:18
• Well, I would want to basically have nested children, so a json object that represented the same as a 'folder tree', if that makes sense. I guess I would have to recursively iterate through it in order to save. – dzm Commented Oct 23, 2013 at 2:22

3 Answers 3

You can do it like this:

var arr = [] //your array;
var tree = {};

function addnode(obj){
  var splitpath = obj.path.replace(/^\/|\/$/g, "").split('/');
  var ptr = tree;
  for (i=0;i<splitpath.length;i++)
  {
    node = { name: splitpath[i],
    type: 'directory'};
    if(i == splitpath.length-1)
    {node.size = obj.size;node.type = obj.type;}
    ptr[splitpath[i]] = ptr[splitpath[i]]||node;
    ptr[splitpath[i]].children=ptr[splitpath[i]].children||{};
    ptr=ptr[splitpath[i]].children;
  }    
}

arr.map(addnode);
console.log(require('util').inspect(tree, {depth:null}));

Output

{ storage:
   { name: 'storage',
     type: 'directory',
     children:
      { test:
         { name: 'test',
           type: 'directory',
           size: 0,
           children:
            { asdf:
               { name: 'asdf',
                 type: 'directory',
                 size: 170,
                 children: { '2.txt': { name: '2.txt', type: 'file', size: 0, children: {} } } } } } } } }

Assuming / will never show up in the list of files, something like this should work:

function treeify(files) {
  var path = require('path')

  files = files.reduce(function(tree, f) {
    var dir = path.dirname(f.path)

    if (tree[dir]) {
      tree[dir].children.push(f)
    } else {
      tree[dir] = { implied: true, children: [f] }
    }

    if (tree[f.path]) {
      f.children = tree[f.path].children
    } else {
      f.children = []
    }

    return (tree[f.path] = f), tree
  }, {})

  return Object.keys(files).reduce(function(tree, f) {
    if (files[f].implied) {
      return tree.concat(files[f].children)
    }

    return tree
  }, [])
}

It'll turn the array you mention in the question in to something like this:

[ { name: 'test',
    size: 0,
    type: 'directory',
    path: '/storage/test',
    children: 
     [ { name: 'asdf',
         size: 170,
         type: 'directory',
         path: '/storage/test/asdf',
         children: 
          [ { name: '2.txt',
              size: 0,
              type: 'file',
              path: '/storage/test/asdf/2.txt',
              children: [] } ] } ] } ]

I haven't actually tested this with any other data sources, so your milage may vary but at least it ought to nudge you in the right direction.

Solution based on @user568109 but returning results in arrays instead of objects:

function filesToTreeNodes(arr) {
  var tree = {}
  function addnode(obj) {
    var splitpath = obj.fileName.replace(/^\/|\/$/g, "").split('/');
    var ptr = tree;
    for (let i = 0; i < splitpath.length; i++) {
      let node: any = {
        fileName: splitpath[i],
        isDirectory: true
      };
      if (i == splitpath.length - 1) {
        node.isDirectory = false
      }
      ptr[splitpath[i]] = ptr[splitpath[i]] || node;
      ptr[splitpath[i]].children = ptr[splitpath[i]].children || {};
      ptr = ptr[splitpath[i]].children;
    }
  }
  function objectToArr(node) {
    Object.keys(node || {}).map((k) => {
      if (node[k].children) {
        objectToArr(node[k])
      }
    })
    if (node.children) {
      node.children = Object.values(node.children)
      node.children.forEach(objectToArr)
    }
  }
  arr.map(addnode);
  objectToArr(tree)
  return Object.values(tree)
}

This is the signature to better understand the input / output formats:

export interface TreeNode {
  isDirectory: string
  children: TreeNode[]
  fileName: string
}
export interface File {
  fileName: string
}
export type fileToTreeNodeType = (files: File[]) => TreeNode[]