non_deterministic_sw_eng: Instructions file for GitHub Copilot

GitHub Copilot Instructions

This file provides project-wide instructions for GitHub Copilot.

Project Overview

E-commerce platform built with:

• Frontend: React 18, TypeScript, TailwindCSS
• Backend: Node.js 20, Express 4, TypeScript
• Database: PostgreSQL 16 with Prisma ORM
• Auth: OAuth2 with JWT tokens

Code Standards

TypeScript

• Use strict mode, avoid any types
• All functions require explicit return types
• Use interfaces for object shapes
• Prefer const over let

React

• Functional components only (no class components)
• Use custom hooks for shared logic
• Props interfaces named {ComponentName}Props
• Use React Query for server state management

API Design

• RESTful endpoints following naming conventions
• Use zod schemas for request validation
• Standardized error responses
• All endpoints require authentication unless explicitly public

Testing Requirements

• Minimum 80% coverage for new code
• Table-driven tests for utilities
• Integration tests for API endpoints
• Use React Testing Library for components

Security Requirements

• Validate all user input at API boundary
• Use parameterized queries only
• Never hardcode secrets
• Sanitize output for XSS prevention

Key Patterns

API Calls

// Use the API service, never raw fetch
import { api } from '@/services/api';
const users = await api.users.list();

Error Handling

import { ApplicationError, ErrorCode } from '@/errors';
throw new ApplicationError(ErrorCode.NOT_FOUND, 'User not found');

Reference Files

• Component example: src/components/UserProfile/
• Service pattern: src/services/authService.ts
• Test example: src/utils/__tests__/