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?

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

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 Event loop Run JavaScript in background threads Main thread

Question 5

What is the difference between shallow copy and deep copy?

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

Question 6

What is memoization?

Recursion Function composition Memory leak Caching function results to improve performance

Question 7

What is the event delegation pattern?

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

Question 8

What are symbols in JavaScript?

Unique and immutable primitive values Strings Objects Numbers

Question 9

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

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

Question 10

What is the "new" operator doing?

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

Question 11

What are WeakMap and WeakSet?

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

Question 12

What is currying in JavaScript?

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

Question 13

What is the observer pattern?

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

Question 14

How does the JavaScript engine handle memory management?

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

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?

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

Question 17

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

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

Question 18

What are decorators in JavaScript (proposal)?

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

Question 19

What is a Service Worker?

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

Question 20

What is the "composite" pattern in JavaScript?

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