type Upper = Uppercase<"hello">;↵
type Lower = Lowercase<"WORLD">;↵
type Cap = Capitalize<"typescript">;↵
type Uncap = Uncapitalize<"TypeScript">;↵
type EventName<T extends string> = `on${Capitalize<T>}`;↵
type ClickEvent = EventName<"click">;↵
type SubmitEvent = EventName<"submit">;↵
const upper: Upper = "HELLO";↵
const lower: Lower = "world";↵
const cap: Cap = "Typescript";↵
const uncap: Uncap = "typeScript";↵
console.log(`${upper} ${lower}`);↵
console.log(`${cap} - ${uncap}`);