Basics of JavaScript

Start your journey with the fundamental syntax of JavaScript. Every great developer builds on a rock-solid foundation.

Variables

Variables are the "containers" for storing data in your application.

• const: For values that won't change. This is the preferred default.
• let: For values that may change over time.
• var: The old way. Avoid using it due to its tricky scoping rules (hoisting).

const birthYear = 1990;
let age = 34;
age = 35; // Fine with 'let'

Data Types

JavaScript has two main categories of data types:

1. Primitives (Atomic)

• String: "Hello"
• Number: 42, 3.14
• Boolean: true / false
• Undefined: A variable declared but not assigned.
• Null: Explicitly "nothing."
• Symbol: Unique identifiers.
• BigInt: For massive numbers.

2. Objects (Complex)

Objects are collections of key-value pairs. Arrays are also technically objects in JS.

const user = {
    name: "Alex",
    age: 25,
    isDev: true
};

Operators

• Arithmetic: +, -, *, /, %
• Assignment: =, +=, -=
• Comparison: === (Strict equality - Always use this!), !==, >, <
• Logical: && (AND), || (OR), ! (NOT)

Control Flow

Control flow allows your program to make decisions.

1. Conditional Logic (if/else)

if (age >= 18) {
    console.log("Welcome!");
} else {
    console.log("Wait till you're older.");
}

2. Loops (for, while)

for (let i = 0; i < 5; i++) {
    console.log(`Iteration: ${i}`);
}

Next Step: High-level understanding of How it Works.