00298-medium-length-of-string.ts

// ============= Test Cases =============
import type { Equal, Expect } from './test-utils'

type cases = [
  Expect<Equal<LengthOfString<''>, 0>>,
  Expect<Equal<LengthOfString<'kumiko'>, 6>>,
  Expect<Equal<LengthOfString<'reina'>, 5>>,
  Expect<Equal<LengthOfString<'Sound! Euphonium'>, 16>>,
]


// ============= Your Code Here =============
type LengthOfString<S extends string, T extends any[] = []> = S extends `${infer R}${infer P}` ? LengthOfString<P, [...T,R]> : T['length']