Function overloading in TypeScript allows you to define multiple functions with the same name but different parameters. This can be useful when you want to provide different behavior based on the arguments passed to the function. By using function overloading, you can improve the return types of your functions for different input scenarios.
TypeScript 2.1 introduced mapped types, which allow you to create new types based on the properties of an existing type. For example, you can create a mapped type that has the same keys as an existing type, but with optional values.
TypeScript 3.4 introduced const assertions, which allow you to claim a value as immutable. This is useful when working with arrays, as it prevents new values from being added to an existing array.
TypeScript 3.8 introduces a new feature called top-level await. It allows developers to use the `await` keyword without a surrounding `async` function at the top level of a module.