Essential TypeScript patterns and practices for building scalable applications. Learn about type safety, interfaces, and advanced typing techniques.

Setting Up TypeScript

When starting a new TypeScript project, it's important to configure your tsconfig.json properly. Enable strict type checking, set your target to a modern JavaScript version, and configure your module resolution. A good starting point is to use the strictest settings possible and gradually relax them as needed.

Defining Interfaces and Types

Use interfaces for object shapes and classes, and use types for primitives, unions, and intersections. Create reusable interfaces for common data structures like API responses, user profiles, and configuration objects. This makes your code more maintainable and self-documenting.

Utility Types

TypeScript provides many utility types like Partial, Required, Pick, Omit, and Record. These help you transform existing types into new ones without duplicating definitions. For example, use Partial when you need to make all properties optional, or Pick when you need a subset of properties from an existing type.

Generics

Generics allow you to create reusable components that work with multiple types. Use them for functions, interfaces, and classes that need to operate on various data types. Generics make your code more flexible while maintaining type safety.

Error Handling

Create custom error types and use discriminated unions for error handling. This allows you to handle different error cases in a type-safe way. Consider using Result types or similar patterns for functions that might fail.

Module Organization

Organize your code into logical modules and use barrel exports (index.ts files) to simplify imports. Avoid deeply nested import paths and consider using path aliases in your tsconfig.json to make imports more readable.

By following these TypeScript best practices, you can build large applications that are type-safe, maintainable, and easier to reason about.