Mastering TypeScript Generics

What are Generics?

Generics allow you to create reusable components that work with a variety of types rather than a single one.

Basic Syntax

You can define a generic function using angle brackets.

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

let output = identity<string>("myString");

Constraints

Sometimes you want to limit the types that can be passed to a generic.

"Generics provide a way to make components work with any data type and not restrict to one data type."

Using extends keyof

function getProperty<T, K extends keyof T>(obj: T, key: K) {
  return obj[key];
}