JavaScript Koans: A Journey of Discovery 🧘

Welcome, apprentice, to the JavaScript Koans! This project is designed to help you learn and solidify your understanding of fundamental JavaScript concepts through a series of interactive challenges.

Inspired by traditional Zen Koans, these exercises require you to contemplate and fix "broken" assertions within the code. By replacing the __ placeholders with the correct values, you will mend the code and, in doing so, illuminate your understanding of JavaScript.

The Path Ahead ✨

This collection guides you through several key areas of JavaScript:

1. JavaScript Basics (js_koan_basics.js): Master the foundational elements like if/else statements, while and for loops, and function declarations (including arrow functions).
2. The Blueprint - Classes (js_koan_classes.js): Delve into Object-Oriented Programming in JavaScript. Understand constructors, methods, inheritance (extends, super), static methods, and private fields (#).
3. Asynchronous Wisdom (js_koan_async.js): Explore the non-blocking nature of JavaScript. Learn about Promises, async/await, setTimeout, Promise.all, and making network requests using Workspace (or similar).
4. Handling Requests (js_koan_express.js): Understand server-side logic with Express.js. Learn about handling different HTTP verbs (POST, PUT, DELETE, GET) and returning appropriate HTTP status codes.

Prerequisites

• Node.js: You'll need Node.js installed to run these JavaScript files. Version 18+ is recommended for native Workspace support and modern JavaScript features. You can download it from nodejs.org.
• npm: Node.js comes bundled with npm (Node Package Manager), which is used to install project dependencies.
• Terminal/Command Line: Basic familiarity with using your terminal for commands like cp and node.

Installation 🛠️

1. Clone or Download: Get the project files onto your local machine.

   git clone <your-repository-url> # Don't download the ZIP
   cd <project-directory>

2. Install Dependencies: Open your terminal in the project directory and run:

   npm install

   This will install chalk (for colorful console output), express, and cors (used by the Koans and the simple server).

How to Embark on Your Journey 🚀

1. Copy the Koan File: Before you start editing, make a copy of the Koan file you want to work on. This keeps the original file intact if you need to start over. In your terminal, use the cp command (or manually copy/paste the file using your file explorer):

   • For the Basics Koan: cp js_koan_basics.js basics-koan.js
   • For the Classes Koan: cp js_koan_classes.js classes-koan.js
   • For the Async Koan: cp js_koan_async.js async-koan.js
   • For the Express Koan: cp js_koan_express.js express-koan.js

2. Open Your Working Copy: Open the copied file (e.g., basics-koan.js, express-koan.js) in your code editor.

3. Find the Blanks: Locate the lines containing mustAssert(...) in your copied file. Your task is to replace the __ placeholder within the assertion's condition (e.g., mustAssert(result === __, ...) becomes mustAssert(result === 'expected value', ...)). Do not modify the original js_koan_*.js files.

4. Run Your Working Copy: Execute the copied file using Node.js from your terminal:

   node basics-koan.js

   or

   node classes-koan.js

   or (for the async koan - ensure server.js is running first! See note below.)

   node async-koan.js

   or (for the express koan - runs its own server internally)

   node express-koan.js

5. Observe the Output:

   • If you see green messages (decoded from Base64!), your assertion is correct. The path unfolds!
   • If you see a red 🛑 Assertion Failed: message, you need to rethink your answer for that specific blank in your copied file.

6. Repeat: Continue filling in the blanks in your copied file and running it until all assertions pass for that Koan. Then, copy the next original Koan file (e.g., cp js_koan_classes.js classes-koan.js) and repeat the process.

Special Notes:

• Async Koan (async-koan.js):

  • This Koan includes a section that interacts with a separate, simple web server (server.js).
  • Before running node async-koan.js, you need to start this server. Open a separate terminal window, navigate to the project directory, and run:

    node server.js

  • Keep this server running while you work through async-koan.js. You should see a message like 🔮 Async Koan server listening at http://localhost:1337.

• Express Koan (express-koan.js):

  • This Koan involves creating and interacting with a simple Express.js server within the same file.
  • Unlike the Async Koan, you do not need to start a separate server process. Running node express-koan.js will handle both the server setup and the test requests automatically.

File Structure

.
├── README.md           # This file
├── js_koan_async.js    # Original Koan focusing on asynchronous JavaScript (COPY THIS)
├── js_koan_basics.js   # Original Koan covering JS fundamentals (COPY THIS)
├── js_koan_classes.js  # Original Koan exploring JS classes (COPY THIS)
├── js_koan_express.js  # Original Koan covering Express.js basics (COPY THIS)
├── koan.js             # (Likely a helper or utility script - e.g., containing mustAssert)
├── package-lock.json   # Records exact dependency versions
├── package.json        # Project manifest, lists dependencies (chalk, express, cors)
└── server.js           # Simple Express server for the async koan's fetch exercise

# --> You will create these files by copying the originals:
# basics-koan.js
# classes-koan.js
# async-koan.js
# express-koan.js

Bonus Challenge 🏆

The original js_koan_basics.js file includes a bonus challenge: Create your own Greeter subclass that shouts the greeting in uppercase. Add and test your creation within your basics-koan.js file!

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May your journey be enlightening! Copy the scrolls, fix the assertions, understand the concepts, and emerge a more confident JavaScript developer.