Tag: type-safety

Learn how to replace runtime validation with TypeScript intersection types for compile-time safety and cleaner code.

Learn how to make TypeScript catch missing switch cases at compile time using the exhaustive switch pattern with the never type.

The non-null assertion operator (!) tells TypeScript to trust you when you say a value isn't null or undefined. But this trust comes at a cost: runtime crashes that TypeScript could have prevented. Learn why this operator undermines type safety and what to use instead.

Const assertions provide immutability but lack semantic meaning. Learn how TypeScript's named tuples and readonly arrays combine to give you both type safety and self-documenting code.

An assertion function is a runtime check that identifies the type of unknown input. TypeScript's compiler assumes the input is of the type claimed by the assertion function's signature. Assertion functions are useful for uncertain values, like user input, and generate runtime checks. They can raise errors if the input doesn't meet criteria.