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mbeaudru/modern-js-cheatsheet

★ 25,644Audience · developerComplexity · 1/5StaleLicenseSetup · easy

TLDR

A reference guide explaining modern JavaScript syntax (ES2015+) for developers who know basics but struggle reading real-world code with arrow functions, destructuring, async/await, and other contemporary patterns.

Mindmap

mindmap
  root((repo))
    What it covers
      Arrow functions
      Destructuring
      Async and await
      Template literals
    Key concepts
      Spread operators
      Classes
      Imports exports
      This keyword
    How to use it
      Learning frameworks
      Code review help
      Job onboarding
    Audience
      Intermediate devs
      Framework learners
      Career switchers

Things people build with this

USE CASE 1

Quickly look up what arrow functions or destructuring syntax means while reading a codebase.

USE CASE 2

Prepare for a new job by reviewing modern JavaScript patterns you'll encounter on day one.

USE CASE 3

Learn the syntax foundations before diving into a framework like React or Vue.

USE CASE 4

Understand code examples in documentation or tutorials that use ES2015+ features.

Tech stack

JavaScriptES2015ES6

Getting it running

Difficulty · easy Time to first run · 5min
Use freely for any purpose, including commercial use, as long as you keep the copyright notice and license text.

In plain English

Modern JavaScript Cheatsheet is a reference document, not a software tool, aimed at developers who know basic programming but get confused when reading modern JavaScript code. It targets the gap between "I understand JavaScript fundamentals" and "I can comfortably read real-world codebases or learn frameworks like React." The guide focuses specifically on features introduced in ES2015 (also called ES6), the major 2015 update to JavaScript that is now standard in virtually every codebase. The document explains concepts like arrow functions (a shorter syntax for writing functions), destructuring (a shorthand for extracting values from objects and arrays), Promises and async/await (tools for managing code that runs asynchronously, like fetching data from a server), template literals (a cleaner way to embed variables in strings), spread operators, classes, imports and exports, and how the JavaScript keyword "this" behaves. Each section includes short explanations, code examples, and links to deeper resources. You would use this as a companion while learning a JavaScript framework, starting a new job, or reviewing code written by someone with more experience. It is not a tutorial for absolute beginners but a targeted reference for someone who already has some coding background and needs to decode the syntax patterns they keep encountering in modern projects.

Copy-paste prompts

Prompt 1
I'm reading code with arrow functions and destructuring but don't understand the syntax. Use the Modern JavaScript Cheatsheet to explain what `const { name, age } = person` and `const greet = () => {}` do.
Prompt 2
Show me examples from the Modern JavaScript Cheatsheet of how async/await works and how it compares to Promises.
Prompt 3
I'm starting a new job and see spread operators and template literals everywhere. Explain these using the Modern JavaScript Cheatsheet with real code examples.
Prompt 4
Use the Modern JavaScript Cheatsheet to help me understand what `import` and `export` statements do in a JavaScript module.
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Generated 2026-05-18 · Model: sonnet-4-6 · Verify against the repo before relying on details.