SOLID Generic - TypeScript / Bun / Node.js

Agent Workflow (MANDATORY)

Before ANY implementation, use TeamCreate to spawn 3 agents:

• fuse-ai-pilot:explore-codebase - Analyze project structure and existing patterns

• fuse-ai-pilot:research-expert - Verify latest TypeScript/Bun docs via Context7

• mcp__context7__query-docs - Check integration compatibility

After implementation, run fuse-ai-pilot:sniper for validation.

DRY - Reuse Before Creating (MANDATORY)

Before writing ANY new code:

• Grep the codebase for similar function names, patterns, or logic

• Check shared locations: modules/cores/lib/ , modules/cores/interfaces/ , modules/cores/errors/

• If similar code exists -> extend/reuse instead of duplicate

• If code will be used by 2+ modules -> create in modules/cores/

• Extract repeated logic (3+ occurrences) into shared helpers

Absolute Rules (MANDATORY)

1. Files < 100 lines

• Split at 90 lines - Never exceed 100

• Modules < 80 lines

• Services < 60 lines

• Validators < 40 lines

2. Interfaces Separated (Modular MANDATORY)

modules/[feature]/src/interfaces/ # Feature types |- user.interface.ts - service.interface.ts modules/cores/interfaces/ # Shared types - shared.interface.ts

NEVER put interfaces in implementation files. NEVER use flat src/ structure - always modules/ .

3. JSDoc Mandatory

/**

• Parse configuration from file path.
• @param filePath - Absolute path to config file
• @returns Parsed configuration object
• @throws ConfigError if file is invalid */ export function parseConfig(filePath: string): Config

SOLID Principles (Detailed Guides)

Principle Reference Key Rule

S Single Responsibility single-responsibility.md One file = one reason to change

O Open/Closed open-closed.md Extend via composition, not modification

L Liskov Substitution liskov-substitution.md Implementations honor interface contracts

I Interface Segregation interface-segregation.md Many focused interfaces > one fat interface

D Dependency Inversion dependency-inversion.md Depend on abstractions, inject dependencies

See solid-principles.md for overview and architecture-patterns.md for project structure.

Code Templates

Template Usage Max Lines

module.md TypeScript/Bun module 80

service.md Service with DI 60

interface.md TypeScript interfaces

validator.md Zod validation schemas 40

factory.md Factory pattern 60

error.md Custom error classes 40

test.md Bun test / Vitest

Forbidden

• Files > 100 lines

• Interfaces in implementation files

• Business logic in entry points

• Missing JSDoc on exports

• any type

• Barrel exports (index.ts re-exports)

• Duplicating existing utility without Grep search first

• Copy-pasting logic blocks instead of extracting shared function

• Concrete dependencies without interface abstraction