Master Both Languages Together - A comprehensive dual-language learning platform with 150+ exercises, cross-language projects, and professional development paths.
🎯 Perfect for: Developers learning their second language, full-stack engineers, bootcamp students, and anyone wanting to understand how JavaScript and Java complement each other.
- 🔄 Cross-Language Skills: Understand concepts in both frontend and backend contexts
- 📈 Career Flexibility: Full-stack opportunities with modern JavaScript + enterprise Java
- 🧪 Test-Driven: Every concept tested in both languages (Jest + JUnit)
- 🛠️ Real Projects: Build complete applications with JS frontend + Java backend
- 📚 Comprehensive: Equal coverage of both languages with comparison exercises
- 🤝 Community: Learn from developers skilled in both ecosystems
# 1. Clone and setup
git clone https://github.com/GWizard98/javascript-learning.git
cd javascript-learning && npm install
# 2. Run JavaScript tests
npm test javascript/exercises/basics/sum
# ✓ JavaScript: 3 tests passing
# 3. Try advanced JS concepts
npm test javascript/exercises/oop/classes-and-objects
# ✓ OOP in JavaScript: 25+ tests passing# 1. Test Java setup
cd java && mvn test
# ✓ Java: 70+ tests passing
# 2. Compare with JavaScript
mvn test -Dtest=*OOPTest
# ✓ Same concepts, Java syntax# Full-stack application
cd cross-language-projects/task-manager
# JavaScript frontend + Java backendChoose your learning style: Side-by-side comparison or deep-dive single language
- Week 1-2: Variables & Functions in both JS and Java
- Week 3-4: OOP Concepts - Compare ES6 Classes vs Java Classes
- Week 5-6: Data Structures - Arrays/Collections in both languages
- Week 7-8: 🎯 Capstone: Full-stack app (JS frontend + Java backend)
- Fundamentals →
javascript/exercises/basics/(20+ exercises) - Modern JS →
javascript/exercises/es6-plus/,javascript/exercises/async/ - DOM & Web APIs →
javascript/exercises/dom/(Required for web dev) - Advanced OOP →
javascript/exercises/oop/(ES6 classes, design patterns) - 🎯 Projects →
javascript/projects/(Todo app, interactive sites)
- Core Java →
java/src/main/java/learning/basics/(Variables, Control Flow) - OOP Mastery →
java/src/main/java/learning/oop/(Inheritance, Polymorphism) - Collections & Algorithms →
java/src/main/java/learning/basics/ArraysCollections - Exception Handling →
java/src/main/java/learning/exceptions/ - 🎯 Projects → Spring Boot APIs, enterprise patterns
- Task Manager →
cross-language-projects/task-manager/ - E-commerce Platform → React frontend + Spring Boot backend
- Real-time Chat → WebSocket integration
- Microservices → JavaScript BFF + Java services
java-javascript-learning/
├─ javascript/ # 🟨 JavaScript Learning (50%)
│ ├─ exercises/
│ │ ├─ basics/ # Variables, functions, operators
│ │ ├─ intermediate/ # Array methods, real-world patterns
│ │ ├─ async/ # Promises, async/await, APIs
│ │ ├─ dom/ # Interactive web elements (Required)
│ │ └─ oop/ # ES6 classes, design patterns
│ └─ projects/
│ ├─ calculator/ # Beginner project
│ └─ intermediate-todo-app/ # Advanced patterns
├─ java/ # 🔵 Java Learning (50%)
│ ├─ src/main/java/learning/
│ │ ├─ basics/ # Variables, control flow, strings
│ │ ├─ oop/ # Classes, inheritance, polymorphism
│ │ └─ exceptions/ # Error handling patterns
│ ├─ src/test/java/learning/ # 70+ JUnit tests
│ └─ pom.xml # Maven configuration
├─ cross-language-projects/ # 🔄 Full-Stack Integration
│ └─ task-manager/ # JavaScript frontend + Java backend
│ └─ combination-lab/ # Advanced polyglot demos
├─ docs/
│ ├─ javascript-guide.md # JS-specific documentation
│ ├─ java-guide.md # Java-specific documentation
│ └─ language-comparison.md # Side-by-side concept comparison
└─ WARP.md # Unified dual-language guide
- Parallel Exercises: Same concepts implemented in both languages
- Full-Stack Projects: JavaScript frontend + Java Spring Boot backend
- Comparison Guides: Side-by-side syntax and pattern analysis
- Career Paths: Frontend specialist, Backend specialist, or Full-Stack
- Install dependencies
npm ci || npm install
- Run the test suite
npm test
- Test files live next to their implementations and end with
.test.js. - Use
npm testto run all tests ornpm test -- <pattern>to filter, e.g.:
npm test -- sum
- Create a new file in
exercises/<topic>/yourFunction.js. - Create a matching spec
exercises/<topic>/yourFunction.test.js. - Start with a failing test, implement the function, and iterate.
Example:
// exercises/strings/reverse.js
function reverse(s) { return s.split('').reverse().join(''); }
module.exports = reverse;
// exercises/strings/reverse.test.js
const reverse = require('./reverse');
test('reverses a string', () => {
expect(reverse('abc')).toBe('cba');
});
- Basics: functions, numbers, strings
- Data structures: arrays, objects, maps/sets
- Control flow: conditionals, loops, iteration
- ES6+ features: arrow functions, destructuring, spread/rest, modules
- Error handling: try/catch, custom errors
- Async JS: promises, async/await, fetch
- Testing: mocking, coverage, testing strategies
- Bonus: DOM basics (optional), TypeScript primer (optional)
Complete Java fundamentals with 70+ tests covering:
- Variables, data types, and type conversion
- String manipulation and StringBuilder
- Control flow: loops, conditionals, algorithms
- Arrays, Collections (ArrayList, HashMap)
- Object-Oriented Programming: inheritance, polymorphism
- Exception handling with custom exceptions
# Quick start with Java bonus content
cd java-bonus/
mvn test # Run all 70+ Java testsSee java-bonus/WARP.md for complete Java instructions.
$ npm test -- array-methods
PASS exercises/intermediate/array-methods.test.js
✓ transforms user data for UI display (15ms)
✓ calculates e-commerce cart totals with tax (8ms)
✓ groups sales data by region/product (12ms)
✓ implements smart search with ranking (22ms)
✓ validates form data with custom rules (18ms)
✓ processes API responses with error handling (31ms)
Test Suites: 1 passed, 1 total
Tests: 25 passed, 25 total
Time: 2.847s- Features: Local storage, filtering, bulk operations, inline editing
- Skills: ES6 classes, event handling, data validation, error recovery
- Real-world patterns: MVC architecture, defensive programming
- Try it: Open
projects/intermediate-todo-app/index.html
- Features: Scientific operations, history, keyboard shortcuts
- Skills: Functions, error handling, DOM manipulation
- Growth path: From basic math to complex expressions
“Went from zero JavaScript knowledge to landing my first frontend job in 3 months using this repo!” - Sarah M., Junior Developer
“The progressive structure and real projects made all the difference. Finally understood async/await!” - Mike L., Career Switcher
“Used this to transition from Java to JavaScript. The bonus Java section helped bridge concepts!” - David K., Full-Stack Developer
- Discussions: Ask questions, share projects
- Issues: Report bugs, request features
- Study Groups: Weekly virtual meetups (check Discussions)
- Good First Issues: Perfect entry points for contributors
- Code Review Program: Get feedback from experienced developers
- Exercise Creation: Help build new challenges for fellow learners
- Mentorship: Connect with successful graduates
Earn badges as you progress:
- 🥉 First Steps: Complete first 5 exercises
- 🥈 Function Master: Complete all function exercises
- 🥇 Async Expert: Master promises and async/await
- 🏆 Project Builder: Complete first milestone project
- 🌟 Community Contributor: Submit your first PR
- Follow the exercises-first pattern and always include tests.
- Keep functions single-purpose and readable.
- See CONTRIBUTING.md for branching, commit style, and PR guidelines.
ISC © Contributors