JavaScript Basics Overview

JavaScript - Base

• JavaScript is the ubiquitous language for web client development
• It's used directly or indirectly, as other languages often extend or compile to it.
• Other languages, like CoffeeScript, Dart, and TypeScript, use JavaScript
• WebAssembly (wasm) is an alternative but its success is yet uncertain.
• It's a low-level bytecode format for in-browser client-side programming, suitable for web compilation.
• JavaScript is also used on server-side platforms, such as Node.js and in various domains like game engines, spreadsheets, or IoT systems.

Summary

• The presentation covers JavaScript's introduction, history, data types, syntax, loops, arrays, objects, functions and many other elements
• Key JavaScript standards include ECMA
• The history of JavaScript editions from 1995-2024 is documented
• Different JavaScript engines associated with browsers, such as V8 (Chrome/Opera), SpiderMonkey (Firefox), Chakra, and JavaScriptCore, are mentioned
• Core Language characteristics like syntax basis, interpreted language, dynamic language, loosely typed, and its multi-paradigm features are highlighted

1. Introduction and History

• JavaScript was introduced in 1995 in Netscape Navigator 2.0 with the name Mocha
• Later, Netscape submitted it for standardization to ECMA
• A standard for ECMAScript (JavaScript) language called ECMAScript-262 was subsequently created
• JavaScript versions, from the 1st to the 15th edition, were highlighted through history
• The evolution through different editions is a key feature of the history

2. Basic Syntax and Semantic

• JavaScript is case-sensitive
• Comments use // for single-line and /* */ for multi-line
• Unicode is utilized, including escape sequences
• Semicolons are optional, but their use is recommended

3. Data Types

• Primitive types include String, Number, Boolean, Null, and Undefined
• Composite types comprise Objects, Arrays, Functions, Dates and RegExps
• Numbers in JavaScript are handled as floating-point values
• JavaScript has a dynamic typing system; variable types can change at runtime
• Special values and functions for handling conversions
• Wrapping objects (e.g., Number, String) are explained. These wrap primitives and add functions like .length
• String literals may use single or double quotes but not both in one string, including escape characters

4. Loop and Control Statements

• Control, if, else; and loop statements (while, do-while, for, for...in, switch, and try...catch) are covered, illustrating syntax and providing examples.
• Syntax is similar to C, C++, and Java.

5. Arrays

• JavaScript arrays can hold various data types (numbers, strings, booleans, objects).
• Arrays are zero-indexed. The first element is at index 0
• Arrays support standard loop through numeric indices and for-in loops
• Several array functions (e.g. forEach,map, filter,every,some, reduce, splice)
• Array operations like .push, .unshift, pop, .shift, .splice, .slice and .length are discussed with examples

6. Objects

• JavaScript is object-based, not class-based.
• Objects are collections of key-value properties.
• Properties can be functions (methods)
• Objects are created through literals or by using constructors; for-in loop can be used to iterate over object properties.
• Object.create can be utilized to create objects by cloning or extending prototypes
• Object properties, methods of access (obj.property, obj["property"])

7. Functions

• JavaScript functions are objects
• They support first-class functions (assigning, passing, returning functions as arguments)
• Defining functions by declaration or using anonymous functions with examples.
• Parameters mismatch cases (less or more parameters than expected).
• Accessing parameters via arguments object

8. Best Practices

• Use strict mode, particularly with JavaScript code to enhance performance and prevent potential errors.
• Adherence to coding style conventions, such as using camelCase for variables, using capital initial letters for constructors, and upper case for constants is essential, especially for maintainability and readability.
• Use linters (e.g., JSLint) or equivalent tools to ensure code quality, identify syntax errors, and follow coding style rules.

Bibliography

• A section listing the sources for the JavaScript presentation materials. The bibliography includes links to useful resources.