Beat Mix - Drum Machine (Code Academy Project)

A drum machine application built as part of a backend development course. This project implements the core logic for managing drum patterns and presets.

Project Overview

This task focused on building the logic for a drum machine app. The main objectives were to:

• Create and manage four drum arrays (kicks, snares, hi-hats, ride cymbals)
• Write functions to toggle, clear, and invert drum steps
• Creating a middlewear server function that recives GET and PUT requests, checks, and sends a response with status codes
• Run tests on the functions and passed all tests (38/38) ✅

Implementation

script.js - Core Drum Logic

Contains the essential functions for managing drum patterns:

• toggleDrum(drumType, id): Toggles a drum step at a specific index (0-15) in the specified drum array. Includes validation for missing arguments, out-of-range indices, and invalid drum types.

• clear(drumType): Sets all values in a drum array to false. Validates the drum type before clearing.

• invert(drumType): Flips all boolean values in a drum array. Validates the drum type before inverting.

Each function includes proper error handling to prevent mutations when called with invalid arguments.

presetHandler.js - Preset Management

The presetHandler function manages saving and loading drum machine presets on the server:

• GET requests: Retrieves a preset at a given index
• PUT requests: Updates/saves a preset at a given index with a new drum array
• Returns appropriate HTTP status codes:
  • 200 for successful operations
  • 400 for invalid request methods
  • 404 for out-of-range indices

Testing

Run the test suite with:

npm test

All 38 tests pass, covering:

• Drum array initialization and uniqueness
• Function validation and edge cases
• Error handling for invalid inputs
• Preset GET/PUT operations with proper status codes

Getting Started

1. Install dependencies: npm install
2. Start the server: npm start
3. Open index.html in a browser

Technologies

• JavaScript (ES6+)
• Node.js / Express
• Mocha / Chai (testing)