Understanding TypeScript Generics

What are Generics?

Generics allow you to write reusable code that works with multiple types.

Basic Example

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

const result = identity<string>("hello")

Generic Constraints

You can constrain generics to specific types:

interface HasLength {
  length: number
}

function logLength<T extends HasLength>(arg: T): void {
  console.log(arg.length)
}

Generics are one of the most powerful features of TypeScript.