TypeScript Best Practices for Enterprise Applications

TypeScript Best Practices for Enterprise Applications

Introduction

[Explain TypeScript's role in maintainability, developer confidence, and API clarity at scale.]

Prerequisites

• Node.js 18+
• TypeScript compiler installed (npm install --save-dev typescript)
• Project using modules & build tooling

Architecture Essentials

Step-by-Step Guide

Step 1: Enable Strict Mode

{
  "compilerOptions": {
    "strict": true,
    "noImplicitAny": true,
    "strictNullChecks": true
  }
}

Step 2: Domain Model Organization

// domain/orders/types.ts
export interface Order {
  id: string;
  customerId: string;
  total: number;
  status: "Pending" | "Paid" | "Cancelled";
}

Step 3: Utility Types & Generics

function paginate<T>(items: T[], page: number, size: number): T[] {
  return items.slice((page - 1) * size, page * size);
}

Step 4: Runtime Validation Integration

import { z } from "zod";
const OrderSchema = z.object({ id: z.string(), total: z.number().nonnegative() });

Best Practices

• Embrace strict typing (avoid any)
• Use discriminated unions for workflow states
• Separate DTOs from domain models

Common Issues & Troubleshooting

Issue: Type widening unexpectedly
Solution: Add explicit generic or const assertions

Issue: JSON payload mismatch
Solution: Introduce runtime schema validation (zod/io-ts)

Key Takeaways

• Strict configuration prevents latent bugs.
• Structural typing + runtime validation improves reliability.
• Clear module boundaries scale team collaboration.

Next Steps

• Add ESLint rules for consistency
• Introduce type-safe API layer (e.g., tRPC)

Additional Resources

• TypeScript Handbook
• Effective TypeScript
• tsconfig Options

What TypeScript pattern most improved your code quality?