JavaScript and Frontend Development Complete Guide

Table of Contents

JavaScript Fundamentals

Dynamic Typed Languages

A dynamically typed language is one where variable types are determined at runtime rather than at compile time. In JavaScript:

Variables don't require explicit type declarations
The same variable can hold different types during execution
Type checking happens during program execution
Types are associated with values, not variables

let x = 10;        // x is a number
x = "Hello";       // Now x is a string
x = true;          // Now x is a boolean

TypeScript

TypeScript is a superset of JavaScript that adds static typing. It compiles to plain JavaScript but provides additional features like:

Static type checking
Interface definitions
Class-based object-oriented programming
Generics
Enums