Updating JSON structure based on id

I was trying to update the town name in the below-given JSON structure.

    "City":[
   {
      "Name":"Delhi",
      "id":"c5d58bef-f1c2-4b7c-a6d7-f64df12321bd",
      "Towns":[
         {
            "Name":"MG Colony",
            "conditionId":"60d1f5eb-0222-4a84-879b-6699b0cfc1a4",
            "cid":"c5d58bef-f1c2-4b7c-a6d7-f64df12321bd"
         },
         {
            "Name":"DLF Colony",
            "conditionId":"60d1f5eb-0222-4a84-879b-7749b0cfc1a4",
            "cid":"c5d58bef-f1c2-4b7c-a6d7-f64df12321bd"
         }
      ]
   },
   {
      "Name":"Pune",
      "id":"c5d58bef-f1c2-4b7c-a6d7-f64df12321ax",
      "Towns":[
         {
            "Name":"Hadapsar",
            "conditionId":"60d1f5eb-0222-4a84-879b-6699b0cfc1x4",
            "cid":"c5d58bef-f1c2-4b7c-a6d7-f64df12321ax"
         },
         {
            "Name":"Magarpatta",
            "conditionId":"60d1f5eb-0222-4a84-879b-7749b0cfc1f4",
            "cid":"c5d58bef-f1c2-4b7c-a6d7-f64df12321bax"
         }
      ]
   }
]

I wanted to change the town name from "Hapdasar" to "Viman Nagar" if my cid matches that of Hadapsar Town

Output which I wanted was:

   "City":[
   {
      "Name":"Delhi",
      "id":"c5d58bef-f1c2-4b7c-a6d7-f64df12321bd",
      "Towns":[
         {
            "Name":"MG Colony",
            "conditionId":"60d1f5eb-0222-4a84-879b-6699b0cfc1a4",
            "cid":"c5d58bef-f1c2-4b7c-a6d7-f64df12321bd"
         },
         {
            "Name":"DLF Colony",
            "conditionId":"60d1f5eb-0222-4a84-879b-7749b0cfc1a4",
            "cid":"c5d58bef-f1c2-4b7c-a6d7-f64df12321bd"
         }
      ]
   },
   {
      "Name":"Pune",
      "id":"c5d58bef-f1c2-4b7c-a6d7-f64df12321ax",
      "Towns":[
         {
            "Name":"Viman Nagar",
            "conditionId":"60d1f5eb-0222-4a84-879b-6699b0cfc1x4",
            "cid":"c5d58bef-f1c2-4b7c-a6d7-f64df12321ax"
         },
         {
            "Name":"Magarpatta",
            "conditionId":"60d1f5eb-0222-4a84-879b-7749b0cfc1f4",
            "cid":"c5d58bef-f1c2-4b7c-a6d7-f64df12321bax"
         }
      ]
   }
]

I was using js map to iterate but was confused about how to replicate the exact structure.

>Solution :

Well, map alone is not enough to solve your problem, since you have two nested arrays. Maybe you can consider the possibility to use maptwice?
For example:

var cid = "c5d58bef-f1c2-4b7c-a6d7-f64df12321ax";
var newName = "Viman Nagar";
City = City.map(function(city) {
  city.towns = city.towns.map(function(town) {
    if (town.cid === cid)
      town.name = newName;
    return town;
  });
  return city;
});