JavaScript find Object Property

Question

I want to find the attributes I want inside the object.
There is one object.

let obj = {
  1: {
    2 : {
      3: {
        4: {
          5: {

          }
        }
      },
      100: {

      }
    }
  },
  6: {
    7: {
      8: {
      }
    },
    14:{

    }
  },
  11: {
    12: {

    },
    13:{

    }
  }
}
console.log(obj.hasOwnProperty(1)); // true
console.log(obj.hasOwnProperty(6)); // true
console.log(obj.hasOwnProperty(2)); // false
console.log(obj.hasOwnProperty(3)); // false

I want to get true results when I search with 2(others).

What should I do?

I wrote something similar for another question - it and the other answers might help. — VLAZ
– VLAZ, Commented Nov 16, 2018 at 7:31

CertainPerformance · Accepted Answer · 2018-11-16 07:22:38Z

You'll need a recursive function. One option is to test whether some of the entries either have the property you're looking for, or if the entry's value is an object, and that object passes the recursive test:

let obj={1:{2:{3:{4:{5:{}}},100:{}}},6:{7:{8:{}},14:{}},11:{12:{},13:{}}}

function hasNestedProp(obj, findProp) {
  findProp = String(findProp);
  return Object.entries(obj).some(([key, val]) => {
    return (
      key === findProp
      || typeof val === 'object' && hasNestedProp(val, findProp)
    );
  });
}

console.log(hasNestedProp(obj, 1));
console.log(hasNestedProp(obj, 6));
console.log(hasNestedProp(obj, 2));
console.log(hasNestedProp(obj, 3));
console.log(hasNestedProp(obj, 555));

Or, more concisely, if you pass in string values instead (properties are always strings, after all):

let obj={1:{2:{3:{4:{5:{}}},100:{}}},6:{7:{8:{}},14:{}},11:{12:{},13:{}}}

const hasNestedProp = (obj, findProp) => (
  Object.entries(obj).some(([key, val]) => (
    key === findProp
    || typeof val === 'object' && hasNestedProp(val, findProp)
  ))
)

console.log(hasNestedProp(obj, '1'));
console.log(hasNestedProp(obj, '6'));
console.log(hasNestedProp(obj, '2'));
console.log(hasNestedProp(obj, '3'));
console.log(hasNestedProp(obj, '555'));

Nikhil Aggarwal · Accepted Answer · 2018-11-16 07:27:56Z

For nested object, you will need to check for each sub-object as well. Try following

let obj={1:{2:{3:{4:{5:{}}},100:{}}},6:{7:{8:{}},14:{}},11:{12:{},13:{}}}

function hasKey(o, key) {
  for(let k in o) {
    if(k == key) return true;
    else if(typeof o[k] === "object" && hasKey(o[k], key)) return true;
  }
  return false;
}

console.log(hasKey(obj, 1)); // true
console.log(hasKey(obj, 6)); // true
console.log(hasKey(obj, 2)); // true
console.log(hasKey(obj, 3)); // true

jilykate · Accepted Answer · 2018-11-16 07:33:50Z

1

you might consider loadash _.get as an option. the following is their example:

var object = { 'a': [{ 'b': { 'c': 3 } }] };

_.get(object, 'a[0].b.c');
// => 3

_.get(object, ['a', '0', 'b', 'c']);
// => 3

_.get(object, 'a.b.c', 'default');
// => 'default'

answered Nov 16, 2018 at 7:33

jilykate

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Comments

Yosvel Quintero · Accepted Answer · 2018-11-16 07:57:13Z

1

You can use Object.keys() combined with Array.prototype.reduce()

Code:

const obj = {1:{2:{3:{4:{5:{}}},100:{}}},6:{7:{8:{}},14:{}},11:{12:{},13:{}}};
const hasKey = (obj, key) => Object
  .keys(obj)
  .reduce((a, c) => {
    if (c == key || typeof obj[c] === 'object' && hasKey(obj[c], key)) {
      a = true;
    }
    return a;
  }, false);

console.log(hasKey(obj, 1));
console.log(hasKey(obj, 6));
console.log(hasKey(obj, 2));
console.log(hasKey(obj, 3));
console.log(hasKey(obj, 555));

edited Nov 16, 2018 at 7:57

answered Nov 16, 2018 at 7:50

Yosvel Quintero

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