Mapped types and template literal types let you transform and generate types programmatically. Here's how to use them in real code.

Discriminated unions are TypeScript's most powerful pattern for modeling state. Here's how to use them to make impossible states unrepresentable.

Constraints, conditional types, infer, and variance — TypeScript generics go deep. Here's how to actually understand them.

TypeScript's strict mode enables 7 checks that catch real bugs. Here's exactly what each one does and why they matter.

Stop writing repetitive type definitions. These built-in TypeScript utility types handle the patterns you keep reinventing.