Object-Oriented JavaScript — JS Technical Interview Questions & Answers

Modelling real-world entities as objects.

Object-Oriented JavaScript

  • Object-Oriented JavaScript (js oop intro) is a JS topic. In plain words you use it for let total = 0 in a cart script. Don’t start with a slogan — start with that picture.
  • Smallest example: let for change, const for fixed. Type it, run it, and say what you see. If you can do that from memory, you know Object-Oriented JavaScript (js oop intro).
  • From the example next to this theory: Modelling real-world entities as objects.
  • Trap: var leak / const reassign. Fix that before you talk about advanced JS.
  • Viva: what is Object-Oriented JavaScript (js oop intro)? Then show let for change, const for fixed. Then name the trap.

Technical Interview Tip: What is Object-Oriented JavaScript (js oop intro)? Show this: let for change, const for fixed. Trap: var leak / const reassign.

Code Examples for Object-Oriented JavaScript

Object-Oriented JavaScript — working example

class Animal {
  static kingdom = "Animalia";
  #secret = "private";
  constructor(name) { this.name = name; }
  speak() { return this.name + " speaks"; }
  reveal() { return this.#secret; }
}
class Dog extends Animal {
  speak() { return super.speak() + " (bark)"; }
}
const d = new Dog("Rex");
console.log(d.speak(), Animal.kingdom, d.reveal());
console.log(Object.getPrototypeOf(d) === Dog.prototype);

Object-Oriented JavaScript — oOP in JS: constructors, prototypes, inheritance, statics, and private fields (#).

How to Explain Object-Oriented JavaScript to an Interviewer

What is Object-Oriented JavaScript (js oop intro)?

Used for let total = 0 a cart script Not just the heading

Give one small example of Object-Oriented JavaScript (js oop intro).

let for change, const for fixed Modelling real-world entities as objects

What mistake do beginners make with Object-Oriented JavaScript (js oop intro)?

var leak / const reassign Show the fix

Where do you use Object-Oriented JavaScript (js oop intro)?

a cart script let total = 0