Object difference in JavaScript

We are required to write a JavaScript function that takes in two objects (possibly nested) and returns a new object with key value pair for the keys that were present in the first object but not in the second

Let's write the code for this function −

Example

const obj1 = {
   "firstName": "Raghav",
   "lastName": "Raj",
   "age": 43,
   "address": "G-12 Kalkaji",
   "email": "raghavraj1299@yahoo.com",
   "salary": 90000
};
const obj2 = {
   "lastName": "Raj",
   "address": "G-12 Kalkaji",
   "email": "raghavraj1299@yahoo.com",
   "salary": 90000
};
const objectDifference = (first, second) => {
   return Object.keys(first).reduce((acc, val) => {
      if(!second.hasOwnProperty(val)){
         acc[val] = first[val];
      };
      return acc;
   }, {});
};
console.log(objectDifference(obj1, obj2));

Output

The output in the console will be −

{ firstName: 'Raghav', age: 43 }