musubix-best-practices

MUSUBIX Best Practices Skill

This skill guides you through applying the 17 best practices learned from MUSUBIX virtual projects.

Overview

MUSUBIX has learned these best practices from implementing 14+ virtual projects. Apply them consistently for high-quality code.

Code Patterns (5)

BP-CODE-001: Entity Input DTO

Use Input DTO objects for entity creation instead of multiple parameters.

// ✅ Recommended: Input DTO
interface CreatePetInput {
  name: string;
  species: string;
  ownerId: string;
}

function createPet(input: CreatePetInput): Pet {
  return new Pet(input);
}

// ❌ Avoid: Multiple parameters
function createPet(name: string, species: string, ownerId: string): Pet {
  // Hard to extend, easy to mix up parameter order
}

BP-CODE-002: Date-based ID Format

Generate IDs with PREFIX-YYYYMMDD-NNN format for sortability.

// ✅ Recommended: Date-based ID
const id = `PET-20260104-001`;  // Sortable, traceable

// ❌ Avoid: UUID only
const id = crypto.randomUUID();  // Not human-readable

BP-CODE-003: Value Objects

Use Value Objects for domain concepts.

// ✅ Recommended: Value Object
interface Price {
  readonly amount: number;
  readonly currency: 'JPY';
}

// ❌ Avoid: Primitive types
const price: number = 1000;  // No currency context

BP-CODE-004: Function-based Value Objects

Use interface + factory function instead of classes for Value Objects.

// ✅ Recommended: Interface + Factory Function
interface Price {
  readonly amount: number;
  readonly currency: 'JPY';
}

function createPrice(amount: number): Result<Price, ValidationError> {
  if (amount < 100 || amount > 1_000_000) {
    return err(new ValidationError('Price must be between 100 and 1,000,000 JPY'));
  }
  return ok({ amount, currency: 'JPY' });
}

// ❌ Avoid: Class-based (doesn't work well with TypeScript structural typing)
class Price {
  private constructor(readonly amount: number) {}
  static create(amount: number): Price { ... }
}