#About

csv2tree is a simple module for converting comma separated values containing parent child relationships into nested hierarchical JSON arrays. This module was created to help analyze data containing parent child relationships represented in a flat format.

##Example Input

id | parent_id | name
--- | ---------- | ---- 1 | 1 | Jim 2 | 1 | Jeff 3 | 2 | John 4 | 4 | Jason 5 | 4 | Jacob 6 | 2 | Jack 7 | 6 | James

In the example data above, each record has an id, and a parent_id. Each parent_id is the parent record's id. For instance, Jim is Jeff's parent because Jim's id is 1, and the parent_id for Jeff is 1.

In csv format, the data is represented as follows:

id,parent_id,name
1,,Jim
2,1,Jeff
3,2,John
4,1,Jason
5,4,Jacob
6,2,Jack
7,6,James

This data is typical of the query output of a table which contains a 1:n parent child relationship where the parent record id refers to the id or primary key of another record in the same table. The data would be much easier to understand visually if it was represented as a nested tree.

##Example Output

[
	{
		"id": "1",
		"parent_id": "",
		"name": "Jim",
		"children": [
			{
				"id": "2",
				"parent_id": "1",
				"name": "Jeff",
				"children": [
					{
						"id": "3",
						"parent_id": "2",
						"name": "John",
						"children": []
					},
					{
						"id": "6",
						"parent_id": "2",
						"name": "Jack",
						"children": [
							{
								"id": "7",
								"parent_id": "6",
								"name": "James",
								"children": []
							}
						]
					}
				]
			},
			{
				"id": "4",
				"parent_id": "1",
				"name": "Jason",
				"children": [
					{
						"id": "5",
						"parent_id": "4",
						"name": "Jacob",
						"children": []
					}
				]
			}
		]
	}
]

This representation of the data is also easily converted to something like a unix style directory tree using a module such as treeify.

##Example Usage

// Read csv data from a file and convert to a JSON tree

var fs = require('fs')
var csv2tree = require('csv2tree')

var data = '~/data.csv'      // Path to file
var id = 'id'                // Name of record ID column in csv data
var parent_id = 'parent_id'  // Name of parent record ID column in csv data

fs.readFile(data, function (csv) {
  csv2tree(csv.toString(), id, parent_id, function (tree) {
    console.log(tree)
  })
})

The csv2tree function requires 4 arguments which must be passed to csv2tree in the correct order. The first argument is the csv data. The second argument is the name of the record id column as it appears in the csv header (you will need to append headers if your csv does not include them). The third argument is the the record id of each record's parent record. The last argument is a callback function, which returns the nested JSON tree.