un-flatten-tree

un-flatten-tree
=========


A small module for converting trees to lists and vice versa. Can be used in browser and Node.

Installation

``bash
$ npm i un-flatten-tree
`

Usage

#### flatten
Converts tree to list.

`javascript
var uft = require('un-flatten-tree');

var tree = [
{name: 'A', items: [
{name: 'B'},
{name: 'C'}
]},
{name: 'D', items: [
{name: 'E', items: []}
]}
];

var list = uft.flatten(
tree,
node => node.items, // obtain child nodes
node => node.name // create output node
);
`

list should be ['A', 'B', 'C', 'D', 'E']

#### unflatten
Converts list to tree.

`javascript
var uft = require('un-flatten-tree');

var list = [
{id: 1, pid: null},
{id: 2, pid: null},
{id: 3, pid: 2},
{id: 4, pid: 3},
{id: 5, pid: 4}
];

var tree = uft.unflatten(
list,
(node, parentNode) => node.pid === parentNode.id, // check if node is a child of parentNode
(node, parentNode) => parentNode.items.push(node), // add node to parentNode
node => ({id: node.id, items: []}) // create output node
);
`

tree should be

`javascript
[
{id: 1, items: []},
{id: 2, items: [
{id: 3, items: [
{id: 4, items: [
{id: 5, items: []}
]}
]}
]}
]
`

More complex examples of usage can be found in tests folder.

$3

This module also contains type declarations.

`typescript
import * as uft from 'un-flatten-tree';

// or

import { unflatten, flatten } from 'un-flatten-tree';
``