Generates Tree menu parent>child relation array

Recursive_Tree_Menu_Gererator.js

const listToTree = (list) => {
  var map = {}
  var node
  var roots = []
  var i
  for (i = 0; i < list.length; i += 1) {
    map[list[i].id] = i // initialize the map
    list[i].children = [] // initialize the children
  }
  for (i = 0; i < list.length; i += 1) {
    node = list[i]
    if (node.parent_id) {
      // if you have dangling branches check that map[node.parent_id] exists
      list[map[node.parent_id]].children.push(node)
    } else {
      roots.push(node)
    }
  }
  return roots
}


var nodes = [
    { id: 1,  title:'News', ref: '#', parent_id: 0 },
    { id: 2,  title:'Entertainment', ref: '#', parent_id: 0 },
    { id: 3,  title:'International', ref: '#', parent_id: 1 },
    { id: 4,  title:'National', ref: '#', parent_id: 1 },
    { id: 5,  title:'Bollywood', ref: '#', parent_id: 2 },
    { id: 6,  title:'Music', ref: '#', parent_id: 2 },
    { id: 7,  title:'Hollywood', ref: '#', parent_id: 2 },
    { id: 30, title:'Pakistan', ref: '#', parent_id: 3 },
    { id: 31, title:'Japan', ref: '#', parent_id: 3 },
    { id: 70, title:'Avatar 2', ref: '#', parent_id: 7 },
    { id: 71, title:'Tom Hanks', ref: '#', parent_id: 7 },
    { id: 72, title:'Anil Kapoor', ref: '#', parent_id: 5 },
    { id: 141, title:'Mahoba', ref: '#', parent_id: 73 },
    { id: 73, title:'Uttar Pradesh', ref: '#', parent_id: 4 },
    { id: 130, title:'James Camroon', ref: '#', parent_id: 70 }
]

return response.status(200).json(listToTreen(nodes))