bracketOperatorGettingProp.js

const user = {
  firstName: 'Akash',
  lastName: 'Rajvanshi',
  fullname: function () {
    return `${this.firstName} ${this.lastName}`
  }
};

console.log(user['first' + 'Name']) // Akash

const name = 'firstName';
console.log(user[name]) //Akash

//That also allows us to access properties whoes keys are not identifiers :
const obj = {
  'first Name': 456
};
console.log(obj['first Name']) // 456

const anotherObj = {
  '6': 'bar'
};
console.log(anotherObj[3 + 3]) // bar (key: the string '6')