Mastering TypeScript: Advanced Patterns and Techniques

TypeScript has revolutionized how we write JavaScript by adding static type checking. But beyond basic types, TypeScript offers powerful advanced features that can significantly improve your code quality.

Advanced Type Patterns

Conditional Types

Conditional types allow you to create types that depend on a condition:

type NonNullable<T> = T extends null | undefined ? never : T;
type Example = NonNullable<string | null>; // string

Mapped Types

Transform existing types into new ones:

type ReadOnly<T> = \{
  readonly [P in keyof T]: T[P];
\};

type User = \{
  name: string;
  email: string;
\};

type ReadOnlyUser = ReadOnly<User>;
// \{ readonly name: string; readonly email: string; \}

Template Literal Types

Create string patterns at the type level:

type EventName<T extends string> = `on$\{Capitalize<T>\}`;
type Click = EventName<"click">; // "onClick"

Utility Types

TypeScript provides many built-in utility types:

• Partial<T>: Makes all properties optional
• Required<T>: Makes all properties required
• Pick<T, K>: Select specific properties
• Omit<T, K>: Exclude specific properties

Best Practices

1. Use strict mode in tsconfig.json
2. Prefer type unions over any
3. Use const assertions for better inference
4. Leverage utility types for transformations

These advanced patterns will help you write more type-safe and maintainable code.