nested tree data normalization

by Ea Bangalore

JavaScript

var data =  [{
  "categories": [{
    "_id": "5a016637e986c90418e96ee9",
    "pid": "0",
    "name": "general-categories"
  }, {
    "priority": 3,
    "name_lower": "tragedy",
    "_id": "5a0d852ce986c9041df2aafb",
    "pid": "5a016637e986c90418e96ee9",
    "name": "Tragedy"
  }, {
    "priority": 3,
    "name_lower": "natural",
    "_id": "5a0d8544e986c9041df2aafd",
    "pid": "5a0d852ce986c9041df2aafb",
    "name": "natural"
  }, {
    "priority": 3,
    "name_lower": "humans",
    "_id": "5a0d8544e986c9041df2aafe",
    "pid": "5a0d852ce986c9041df2aafb",
    "name": "humans"
  }, {
    "priority": 3,
    "name_lower": "earthquake",
    "_id": "5a0d85c6e986c9041df2ab02",
    "pid": "5a0d8544e986c9041df2aafd",
    "name": "earthquake"
  }, {
    "priority": 3,
    "name_lower": "floods",
    "_id": "5a0d85c6e986c9041df2ab03",
    "pid": "5a0d8544e986c9041df2aafd",
    "name": "floods"
  }, {
    "priority": 3,
    "name_lower": "drought",
    "_id": "5a0d85c6e986c9041df2ab04",
    "pid": "5a0d8544e986c9041df2aafd",
    "name": "drought"
  }, {
    "priority": 3,
    "name_lower": "landslides",
    "_id": "5a0d85c6e986c9041df2ab05",
    "pid": "5a0d8544e986c9041df2aafd",
    "name": "landslides"
  }, {
    "priority": 3,
    "name_lower": "tsunami",
    "_id": "5a0d85c6e986c9041df2ab07",
    "pid": "5a0d8544e986c9041df2aafd",
    "name": "tsunami"
  }, {
    "priority": 3,
    "name_lower": "forest-fire",
    "_id": "5a0d85c6e986c9041df2ab09",
    "pid": "5a0d8544e986c9041df2aafd",
    "name": "forest-fire"
  }, {
    "priority": 3,
    "name_lower": "strom",
    "_id": "5a0d85c6e986c9041df2ab0a",
    "pid": "5a0d8544e986c9041df2aafd",
    "name": "strom"
  }, {
    "priority": 3,
    "name_lower": "cyclone",
    "_id": "5a0d85c6e986c9041df2ab0f",
    "pid": "5a0d8544e986c9041df2aafd",
    "name": "cyclone"
  }, {
    "priority": 3,
    "name_lower": "cloud-burst",
    "_id": "5a0d85c6e986c9041df2ab12",
    "pid": "5a0d8544e986c9041df2aafd",
    "name":...