⚙ JavaScript Intro

Variables: const and let

Use const for values that won't be reassigned (most variables). Use let when you need to change the value later. Avoid var — it has confusing scoping rules.

Data types: string ("hello"), number (42, 3.14), boolean (true/false), null, undefined, array ([1,2,3]), object ({key: value}).

Control Flow

if / else if / else — runs code conditionally. Comparison operators: === (strict equal), !==, <, >, <=, >=. Always use === not ==.

for loop: for (let i = 0; i < arr.length; i++). Or modern: for (const item of arr) to iterate arrays.

Template Literals

Use backtick strings for easy variable interpolation: `Hello, ${name}! Score: ${score}` — no more messy string concatenation with + signs.