addFullNameProperty.js

/*
Write a function called "addFullNameProperty".

Given an object that has a "firstName" property and a "lastName" property, "addFullNameProperty" returns a "fullName" property whose value is a string with the first name and last name separated by a space.

var person = {
  firstName: 'Jade',
  lastName: 'Smith'
};
addFullNameProperty(person);
console.log(person.fullName); // --> 'Jade Smith'
*/

function addFullNameProperty(obj) {
  // your code here
  /* START SOLUTION */
  obj.fullName = obj.firstName + ' ' + obj.lastName;
  /* END SOLUTION */
}