Quizzes – EduHub

Question 1

What is the prototype chain and how does it work?

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

Question 2

What are generators in JavaScript?

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

Question 3

What is the Proxy object?

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

Question 4

What are Web Workers?

UI threads Run JavaScript in background threads Event loop Main thread

Question 5

What is the difference between shallow copy and deep copy?

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

Question 6

What is memoization?

Caching function results to improve performance Recursion Memory leak Function composition

Question 7

What is the event delegation pattern?

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

Question 8

What are symbols in JavaScript?

Unique and immutable primitive values Strings Numbers Objects

Question 9

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

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

Question 10

What is the "new" operator doing?

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

Question 11

What are WeakMap and WeakSet?

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

Question 12

What is currying in JavaScript?

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

Question 13

What is the observer pattern?

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

Question 14

How does the JavaScript engine handle memory management?

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

Question 15

What are JavaScript iterators?

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

Question 16

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

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

Question 17

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

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

Question 18

What are decorators in JavaScript (proposal)?

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

Question 19

What is a Service Worker?

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

Question 20

What is the "composite" pattern in JavaScript?

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