Open Source JavaScript Guides

Explore JavaScript through open-source books, tutorials, cheatsheets, exercises, and code examples. This collection spans core language concepts, algorithms and data structures, functional programming, testing, code quality, and application architecture. Whether you’re building your fundamentals or investigating a specific topic, use these resources to learn from practical examples and deepen your understanding of the language.

• JavaScript in One Picture A visual reference that maps core JavaScript concepts into a single diagram, helping learners see how language features relate before exploring each topic in depth. JavaScript in One Picture

• JavaScript Unit Testing Best Practices A practical collection of guidance for writing reliable JavaScript unit tests, including test structure, isolation, naming, maintainability, and common testing mistakes. JavaScript Unit Testing Best Practices

• JavaScript Testing Best Practices A broad guide to effective JavaScript testing, covering unit, integration, and end-to-end testing approaches with advice for building trustworthy automated test suites. JavaScript Testing Best Practices

• You Don’t Need Lodash or Underscore A reference showing how modern JavaScript methods can replace many common Lodash and Underscore utilities, useful when reducing dependencies in browser and Node.js projects. You Don’t Need Lodash or Underscore

• Functional Programming in JavaScript An introduction to functional programming ideas in JavaScript, such as pure functions, immutability, higher-order functions, composition, and declarative problem-solving techniques. Functional Programming in JavaScript

• JavaScript Equality and Type Operators A focused section from the 33 JavaScript Concepts repository that explains the differences among loose equality, strict equality, and the typeof operator. JavaScript Equality and Type Operators

• JavaScript Interview Questions A large collection of JavaScript interview questions and explanations spanning fundamentals, browser behavior, asynchronous programming, modern syntax, and advanced language details. JavaScript Interview Questions

• Itsy Bitsy Data Structures A compact educational project demonstrating how common data structures work by implementing them in JavaScript, including linked lists, stacks, queues, trees, and graphs. Itsy Bitsy Data Structures

• The Modern JavaScript Tutorial A comprehensive JavaScript learning resource with beginner-to-advanced explanations, examples, and browser-focused topics such as DOM manipulation, events, and asynchronous code. The Modern JavaScript Tutorial

• Mostly Adequate Guide to Functional Programming A detailed and approachable book on functional programming concepts using JavaScript, emphasizing composition, purity, functors, monads, and more expressive program design. Mostly Adequate Guide to Functional Programming

• JavaScript: The Good Parts Notes Community notes that summarize and discuss important ideas from Douglas Crockford’s JavaScript-focused work, with emphasis on safer and clearer language patterns. JavaScript: The Good Parts Notes

• JavaScript Arrays and Objects A learning repository focused on working with JavaScript’s core data containers, providing explanations and examples of arrays, objects, methods, and common operations. JavaScript Arrays and Objects

• Clean Code JavaScript A JavaScript adaptation of clean-code principles that promotes readable names, small functions, manageable abstractions, reduced duplication, and easier long-term maintenance. Clean Code JavaScript

• 30 Seconds of Interviews A quick-reference collection of interview questions and short explanations for JavaScript, HTML, CSS, React, and related web-development concepts. 30 Seconds of Interviews

• JavaScript VM Under the Hood An educational exploration of how JavaScript virtual machines execute code, intended to help developers understand parsing, compilation, optimization, and runtime behavior. JavaScript VM Under the Hood

• State-of-the-Art Shitcode A humorous but instructive collection of intentionally poor JavaScript patterns, useful for recognizing confusing, fragile, and difficult-to-maintain code in real projects. State-of-the-Art Shitcode

• JavaScript Tips and Tidbits A collection of small JavaScript discoveries, techniques, and examples that can strengthen everyday coding habits and expose useful language features. JavaScript Tips and Tidbits

• JavaScript Clue Lab A hands-on JavaScript exercise based on the Clue game, designed to practice variables, objects, arrays, functions, and logical problem-solving through code. JavaScript Clue Lab

• JavaScript Questions A set of challenging multiple-choice JavaScript questions that test understanding of coercion, scope, objects, promises, syntax, and language quirks. JavaScript Questions

• Project Guidelines A reference for organizing software projects, covering documentation, architecture, development conventions, version control, testing, and practices that support consistent team collaboration. Project Guidelines

• JavaScript Framework Benchmark A benchmark suite that compares the performance of popular JavaScript frameworks through standardized operations such as rendering, updating, selecting, and removing rows. JavaScript Framework Benchmark

• JavaScript Algorithms and Data Structures A major educational repository with JavaScript implementations of algorithms and data structures, accompanied by explanations that connect theory to executable code. JavaScript Algorithms and Data Structures

• Code Review Tips A concise collection of practices for reviewing code thoughtfully, identifying design and quality concerns, communicating feedback clearly, and improving team codebases. Code Review Tips

• 30 Days of JavaScript A structured JavaScript challenge that progresses from fundamentals to more advanced topics through daily explanations, examples, and practical exercises. 30 Days of JavaScript

• Modern JavaScript Cheatsheet A compact reference to modern JavaScript syntax and features, including ES6+ variables, functions, destructuring, modules, promises, classes, and array methods. Modern JavaScript Cheatsheet

• Domain-Driven Hexagon A guide to applying domain-driven design and hexagonal architecture in software systems, focusing on separating business rules from frameworks, databases, and external services. Domain-Driven Hexagon

• 30 Seconds of Code A library of short JavaScript code snippets that demonstrate reusable solutions for common tasks involving arrays, strings, objects, functions, browser APIs, and algorithms. 30 Seconds of Code

• JavaScript Algorithms A repository of JavaScript algorithm implementations and learning materials, covering sorting, searching, recursion, graph algorithms, dynamic programming, and data structures. JavaScript Algorithms

• JavaScript Tricks and Tips A collection of practical JavaScript techniques intended to improve coding efficiency, clarify common patterns, and provide useful reminders for everyday development. JavaScript Tricks and Tips

• Functional-Light JavaScript A book and learning resource that introduces functional programming in a pragmatic way, using familiar JavaScript patterns rather than requiring purely functional code. Functional-Light JavaScript

• 33 JavaScript Concepts A curated list of essential JavaScript topics, each linked to learning resources, helping developers systematically build a strong understanding of the language. 33 JavaScript Concepts

• JavaScript Notes A repository of JavaScript notes and examples covering key fundamentals, syntax, functions, objects, arrays, DOM concepts, and commonly used language features. JavaScript Notes

• You Don’t Know JS A book series that examines JavaScript’s underlying mechanics, including scope, closures, types, asynchronous behavior, objects, and the this keyword. You Don’t Know JS

• JavaScript Developer Reads A curated collection of articles, tutorials, books, and references for JavaScript developers who want to deepen both practical and conceptual knowledge. JavaScript Developer Reads

• Object References in JavaScript A focused explanation of how JavaScript objects are stored and referenced, helping clarify assignment, mutation, copying, equality, and shared object behavior. Object References in JavaScript

• Awesome JavaScript A curated directory of JavaScript libraries, tools, frameworks, articles, and learning materials organized to help developers discover useful ecosystem resources. Awesome JavaScript

• Best of JS A resource for discovering popular JavaScript projects, libraries, and tools, with project rankings and ecosystem categories that make comparisons easier. Best of JS

• WTFJS A collection of surprising JavaScript behaviors that reveals edge cases involving coercion, comparisons, syntax, and runtime rules, encouraging careful reasoning about the language. WTFJS

• JavaScript Standard Style A JavaScript linter and style guide that enforces a consistent formatting convention automatically, helping teams reduce style debates and catch common issues. JavaScript Standard Style

• JSCamp A JavaScript-focused learning repository with materials and resources intended to help developers study language fundamentals and practical web-development skills. JSCamp

• SurviveJS A collection of resources around JavaScript tooling and web-development topics, particularly focused on learning modern build systems, frameworks, and application development. SurviveJS