Search key and return value in nested object

Question

Lets say my object looks like the below. Its a mix of different arrays and parents, no hierarchical order. e.g.

\"person\": {
\"id\": 12345,
\"name\": \"John Doe         


        

Answer 1

You will need a recursive function. For explanation please check the comments

let person = {
  "id": 12345,
  "name": "John Doe",
  "emergencyContacts": [{
      "name": "Jane Doe",
      "phone": "888-555-1212",
      "relationship": "spouse",
      "moreDetails": {
        "id": 12345,
        "phones": {},
        "home": "800-123-4567",
        "mobile": "877-123-1234"
      }
    },
    {
      "name": "Justin Doe",
      "phone": "877-123-1212",
      "relationship": "parent",
      "mobile": "877-123-1234"
    }
  ],
  "workContacts": [{
      "name": "Jane Doe",
      "phone": "888-555-1212",
      "relationship": "spouse",
      "moreworkDetails": {
        "id": 12345,
        "phones": {},
        "home": "800-123-4567",
        "mobile": "877-123-1236"
      }
    },
    {
      "name": "Justin Doe",
      "phone": "877-123-1212",
      "relationship": "parent",
      "mobile": "877-123-1235"
    }
  ]
}
let arrys = [];

//iterate the object 
function recursive(obj, key) {
  //iterate the object
  for (let keys in obj) {
    // check if the key name is same as the desired one
    if (keys === key) {
      // then push the value to an array
      arrys.push(obj[keys])

    } else {
      // if the value of a key is an array & if it is not empty
      if (Array.isArray(obj[keys]) && obj[keys].length > 0) {
        // iterate the array. in each iteration you will get the object
        // example emergencyContacts. In each iteration 
        // call the same function with new data 
        obj[keys].forEach(function(item) {
          // pass that object to the same function
          recursive(item, key)
        })

      }
      // if the value is an object then again call the same function 
      else if (typeof obj[keys] === 'object') {
        recursive(obj[keys], key)
      }
    }
  }
}

recursive(person, 'mobile');
//create object from the array
let newObj = {}
for (let m = 0; m < arrys.length; m++) {
  newObj[m] = arrys[m]

}
console.log(newObj)