30-seconds-of-code/snippets/dig.md

dig

Return the value in a nested JSON object by the key.

Given the key name (or target), it will look up the key in the object recursively and return the first value if found.

const dig = (obj, target) => {
  if (!obj) return;

  if (obj[target]) return obj[target];
  else {
    return( Object.keys(obj).map(key => {
     if (typeof(obj[key]) === "object") {
        return dig(obj[key], target);
      }
    }).filter(defined => defined)[0] );
  }
};

const data = {
  name: "John Doe",
  details: {
    phone: "9876543210",
    email: "john@example.com",
    address: {
      street: "123 ABC St.",
      state: "CA",
      zip: "98765"
    },
    extra1: {
      nickName: "Johnny"
    },
    extra2: {
      nickName: "JD"
    },
    hobby: "coding",
    snacks: ["chips", 'candy', 'coke']
  },
  l1:{
    l2:{
      l3:{
        l4: "4 levels deep."
      }
    }
  }
};

dig(data, 'nickName'); // "Johnny"
dig(data, 'hobby');    // "coding"
dig(data, 'snacks');   // ["chips","candy","coke"]
dig(data, 'l4');       // "4 levels deep."
dig(data, 'blahblah')  // undefined