Advanced TypeScript Patterns for Type-Safe Applications

Advanced TypeScript Patterns

Generics Generics allow you to write reusable components that work with multiple types:

interface ApiResponse<T> {
  data: T;
  status: number;
  message: string;

async function fetchData<T>(url: string): Promise<ApiResponse<T>> { const response = await fetch(url); return response.json(); } ```

Conditional Types ```typescript type IsString<T> = T extends string ? true : false;

type A = IsString<"hello">; // true type B = IsString<number>; // false ```

Utility Types - `Partial<T>`: Make all properties optional - `Record<K, V>`: Create object types - `Exclude<T, U>`: Remove types from union - `Omit<T, K>`: Remove specific keys - `Pick<T, K>`: Select specific keys

Type Guards ```typescript function isString(value: unknown): value is string { return typeof value === 'string'; } ```

Best Practices - Use strict mode - Avoid `any` type - Create custom types for domain logic - Use discriminated unions for complex state