TypeScript

Introduction

TypeScript is a typed superset of JavaScript that adds static type checking, better editor tooling, and safer refactoring for large applications.

Usage

In our frontend projects, TypeScript is used to:

• Type React component props and state.
• Type API request/response contracts.
• Type utility functions and shared business logic.
• Catch issues during development before runtime.

Official docs: https://www.typescriptlang.org/ 

Security

TypeScript does not replace runtime validation, but it helps reduce bugs that can lead to insecure behavior:

• Prevents common type mismatch mistakes.
• Makes unsafe assumptions easier to spot in code reviews.
• Improves maintainability of auth, API, and validation code paths.

Best Practice

• Enable strict mode (strict: true) in tsconfig.
• Avoid any; prefer explicit and reusable types.
• Use shared types for API contracts to keep frontend/backend aligned.
• Keep types close to domain logic (feature folders or dedicated type modules).
• Use runtime validation (e.g. Zod) for external data, even with TypeScript.