Introduction to JavaScript

Overview

• Popular and widely used programming language.
• Fast-growing with support from major companies (e.g., Netflix, Walmart, PayPal).
• Offers job opportunities as front-end, backend, or full-stack developer.
• Average salary for JavaScript developers in the US: $72,000 annually.

Uses of JavaScript

• Originally used in browsers for interactive web pages.
• Now used for web/mobile apps, real-time applications, command-line tools, and games.
• Supported by large companies and has a strong community.

JavaScript Code Execution

• Runs in browsers via JavaScript engines (e.g., Firefox's SpiderMonkey, Chrome's V8).
• Can also run outside browsers using Node (C++ program embedding V8 engine).
• Provides runtime environments in browsers and Node.

JavaScript vs ECMAScript

• ECMAScript: Specification, maintained by ECMA.
• JavaScript: Language conforming to ECMAScript specification.
• ECMAScript has annual releases, with ES6 introducing new features in 2015.

Setting Up Development Environment

Code Editor

• Recommended: Visual Studio Code (download from code.visualstudio.com).

Node.js

• Optional for JavaScript execution but necessary for third-party libraries.
• Download from Node.js.org.

Creating a Project

• Create a folder and open it in Visual Studio Code.
• Add an index.html file and use basic HTML.
• Install and use the Live Server extension for a simple web server.

Writing JavaScript

• Use the <script> element, best placed at the end of the body for performance reasons.
• Separate JavaScript into external files (index.js) for separation of concerns.

JavaScript Basics

Variables

• Declared using let (modern best practice) or var (older practice).
• Variables can store different data types: string, number, boolean, undefined, null.
• Follow best practices for naming variables: meaningful, no reserved keywords, camel notation.

Constants

• Declared with const, values cannot be changed.
• Use const by default unless re-assignment is needed.

Data Types

• Primitive Types: string, number, boolean, undefined, null.
• JavaScript is dynamically typed - variable types can change at runtime.

Advanced Concepts

Objects

• Used to group related variables (properties).
• Access properties using dot notation or bracket notation.

Arrays

• Used for lists of items, defined with square brackets.
• Arrays are dynamic - can change in size and can store different types.

Functions

• Fundamental building blocks, perform tasks or calculate values.
• Functions can have parameters and return values.
• Distinction between parameters (declaration) and arguments (values).

Conclusion

• Encouragement to continue learning and explore further resources, such as complete courses with certifications.