Javascript Cheatsheets

Welcome to JS Cheatsheets – a comprehensive collection of JavaScript and TypeScript cheatsheets, code snippets, and interactive challenges. Explore practical examples covering syntax, algorithms, system design, and real-world coding problems — perfect for daily practice, interview preparation, or leveling up your JS/TS skills, all demonstrated with clear, runnable code snippets.

This resource is complementary to excellent official documentation and learning platforms like MDN Web Docs, JavaScript.info, and react.dev. If you're just starting out, we highly recommend reading those resources first to build a solid foundation. However, you can also begin with JS Cheatsheets to explore examples in action, reinforce what you learn, or quickly reference key concepts while coding.

🧠 Fundamentals

Learn JS and MDN
A curated collection of practical JavaScript and TypeScript examples, inspired by real-world usage and trusted resources like MDN and JavaScript.info. Includes core features such as the event loop, memoization, loops, recursion, context binding, decorators, and async generators
JS Native
Reimplementation of native JavaScript methods, built-in features, and low-level behavior — understand how they work under the hood.
Theory
Covers deep-dive programming concepts like composition vs inheritance, the call stack, functional patterns, SOLID principles, and detailed examples of type conversions, operator behavior, and equality comparisons in JavaScript.

🏗️ System Design & Architecture

System Design and Patterns
Explore JavaScript implementations of system design concepts: queues, stacks, reducers, async workflows, and more.
Graphs
Graph data structures, traversal algorithms, and visual patterns.

🔢 Algorithms & Utilities

Sorting
Implementations of common sorting algorithms like quicksort, mergesort, and more.
Pick Random
Discover a random JavaScript snippet pulled from the entire cheatsheet collection for daily inspiration or practice.
Lodash
Handy utility functions using the Lodash library.

⚛️ Frameworks & Tools

React
React-focused code snippets covering concepts like children, rendering optimizations, state normalization, and hooks such as useReducer and usePrevious
JavaScript Challenges
Solve hands-on JavaScript coding problems directly in your browser with instant validation and results.

🧪 Miscellaneous

Various
A diverse collection of JavaScript edge cases, patterns, and utilities — from mastering call, bind, and apply to deep cloning, recursive data transforms, closures, and event loop tricks.