weirdusing enum in interface typescript code example

Example 1: typescript enum to string

enum AnEnum {
    One = 1,
    Two = 2
}
let stringOne = AnEnum[1]; // "One"
let stringTwo = AnEnum[AnEnum.Two]; // "Two"

Example 2: ts enum

enum Response {
    No = 0,
    Yes = 1,
}

function respond(recipient: string, message: Response): void {
    // ...
}

respond("Princess Caroline", Response.Yes)