typed-function is a JavaScript library for runtime type-checking and automatic type conversion of function arguments. It allows developers to define typed functions with multiple signatures, union types, and rest parameters, providing informative error messages when invalid arguments are passed. This library is particularly useful for public APIs or functions with complex type-checking logic, as it keeps the function's core logic clean and ensures consistent behavior. It is designed for JavaScript developers who want to add robust type validation to their functions while maintaining flexibility and readability.