What are generics in TypeScript and what are they used for?

Generics in TypeScript are a mechanism that allows creating components (functions, classes, interfaces) that work with different data types while maintaining type safety.

They are used to write reusable code that is not tied to a specific type, but the compiler can still check for type correctness.

Example of a generic function:

function identity<T>(arg: T): T {
  return arg;
}

const num = identity<number>(42); // num has type number
const str = identity<string>("hello"); // str has type string

Here, T is a type parameter that is substituted when the function is called. This allows the function to work with any type, preserving information about the argument's type and the return value.