TypeScript Best Practices 2026: Patterns and Tips

Introduction

TypeScript adoption continues growing. These best practices help you write safer, more maintainable typed code.

Configuration

Enable Strict Mode

In tsconfig.json, set strict: true. Also consider noUncheckedIndexedAccess and exactOptionalPropertyTypes for additional safety.

Type Inference

Let TypeScript infer when types are obvious.

Good - inference is clear:

const name = "John";

const numbers = [1, 2, 3];

Unnecessary over-typing:

const name: string = "John";

When to Annotate

• Function parameters - always annotate
• When inference would be any
• Complex return types

Interface vs Type

Use Interface For:

• Extendable object shapes
• Declaration merging (rare)

Use Type For:

• Unions
• Computed types
• Mapped types

Utility Types

Partial and Required

• Partial<User> - All properties optional
• Required<User> - All properties required

Pick and Omit

• Pick<User, "id" | "name"> - Select specific properties
• Omit<User, "email"> - Exclude properties

Record

• Record<string, User> - Type-safe dictionaries

Avoiding Any

Use Unknown Instead

Bad - any loses all type safety

Good - unknown requires type checking before use

Type Guards

Create functions that narrow types: function isUser(value): value is User

Conclusion

TypeScript is most valuable with strict settings and proper typing patterns. Embrace type inference, master utility types, and avoid any. These practices prevent bugs and improve code quality.