Quizzes – EduHub

Question 1

What is the prototype chain and how does it work?

Array chain Function chain Class chain Objects inherit from other objects; when property not found, lookup goes up the chain

Question 2

What are generators in JavaScript?

Functions that can be paused and resumed with yield Callbacks Async functions Promises

Question 3

What is the Proxy object?

Event proxy Network proxy Server proxy Creates a wrapper to intercept operations on an object

Question 4

What are Web Workers?

Run JavaScript in background threads Main thread UI threads Event loop

Question 5

What is the difference between shallow copy and deep copy?

Same Shallow copies only top-level, deep copies all nested objects Deep copies references Shallow is slower

Question 6

What is memoization?

Memory leak Recursion Caching function results to improve performance Function composition

Question 7

What is the event delegation pattern?

Using parent element to handle events on children Event capturing Event bubbling Event listeners

Question 8

What are symbols in JavaScript?

Objects Strings Numbers Unique and immutable primitive values

Question 9

What is the difference between call, apply, and bind?

All same call/apply invoke immediately with given this and arguments; bind returns a new function bind is immediate apply is for arrays only

Question 10

What is the "new" operator doing?

Declares variable Creates a new object, sets prototype, binds this, returns object Creates array Calls function

Question 11

What are WeakMap and WeakSet?

Regular Map/Set Strong collections Arrays Collections with weak references (no prevention of GC)

Question 12

What is currying in JavaScript?

Partial application Higher-order function Transforming a function with multiple args into sequence of functions with single args Spicy function

Question 13

What is the observer pattern?

Factory Singleton One-to-many dependency where objects notify observers of changes Module

Question 14

How does the JavaScript engine handle memory management?

Manual free No management Automatic garbage collection using mark-and-sweep Reference counting only

Question 15

What are JavaScript iterators?

Loops Objects that define a sequence and a next() method Functions Arrays

Question 16

What is the difference between deep freeze and Object.freeze?

Object.freeze is shallow, deep freeze recursively freezes Same Deep freeze is built-in Object.freeze is deep

Question 17

What is the "optional chaining" operator (?.)?

Null check Ternary operator Safely access nested properties without checking each level Logical OR

Question 18

What are decorators in JavaScript (proposal)?

Production feature Typescript only Experimental feature to modify class behavior declaratively React only

Question 19

What is a Service Worker?

Main thread script Web worker Script that runs in background for offline support and push notifications Event handler

Question 20

What is the "composite" pattern in JavaScript?

Singleton Data pattern UI pattern Compose objects into tree structures to represent part-whole hierarchies