Frontend Interview Master

JavaScript becomes 10x easier when you understand these concepts! 🚀

Most beginners struggle not because JS is hard — but because these terms sound confusing at first. Once you understand them, JS becomes super smooth to work with.
Core Concepts Every JS Developer Should Know:

Async & Promises
🔹 Callback – Function passed into another function
🔹 Promise – A value available later
🔹 async/await – Cleaner async code
🔹 Event Loop – Handles async tasks behind the scenes
🔹 Microtask Queue – Queue for promises
🔹 Promise Chaining – Using .then() repeatedly
🔹 Callback Hell – Too many nested callbacks

Scope & Context
🔹 Closure – Function remembers variables from outer scope
🔹 Lexical Scope – Inner functions access outer variables
🔹 This – Refers to current calling object
🔹 Execution Context – Environment where JS runs code
🔹 Shadowing – Smaller scope overwrites larger scope variable

Functions & Patterns
🔹 Currying – Break function into smaller chained functions
🔹 IIFE – Function that runs immediately
🔹 Debounce – Delay a function until user stops typing/clicking
🔹 Throttle – Limit how often a function runs

Memory & Performance
🔹 Hoisting – JS moves declarations to the top
🔹 Call Stack – Where function calls are managed
🔹 Garbage Collection – JS frees unused memory
🔹 Memory Leak – Unused data staying in memory
🔹 Temporal Dead Zone – Time between declaration & initialization

Objects & Prototypes
🔹 Prototype – Sharing features across objects
🔹 Set & Map – Set = unique values, Map = key-value pairs
🔹 Reference vs Value – Objects by reference, primitives by value

Modern JS Features
🔹 Optional Chaining – Safely access deep properties
🔹 Nullish Coalescing – Returns first non-null/undefined value
🔹 Spread Operator – Copy/expand arrays or objects
🔹 Destructuring – Extract values quickly
🔹 Rest Parameters – ...args collects remaining items
🔹 Immutability – Avoid changing existing values

Type System
🔹 Type Coercion – JS auto converts types
🔹 typeof – Checks data type
🔹 instanceof – Checks if object belongs to class/type
🔹 Falsy Values – Values treated as false
🔹 Truthy Values – Values treated as true
🔹 Short-circuiting – JS skips rest if result is known

DOM & Events
🔹 Event Delegation – One event listener handles many elements

If you're learning JavaScript, bookmark these terms — they will make you a 10x better developer.

Which one took you the longest to understand? Drop a comment below! 👇

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3 weeks ago | [YT] | 1