[Typescript] 99. Hard - CamelCase

Implement CamelCase<T> which converts snake_case string to camelCase.

For example

type camelCase1 = CamelCase<'hello_world_with_types'> // expected to be 'helloWorldWithTypes'
type camelCase2 = CamelCase<'HELLO_WORLD_WITH_TYPES'> // expected to be same as previous one

 

/* _____________ Your Code Here _____________ */
type ToCamelCase<S extends string, ACC extends string = ''> = S extends `${infer F}${infer REST}`
  ? F extends '_'
    ? ToCamelCase<Capitalize<REST>, `${ACC}`>
    : ToCamelCase<REST, `${ACC}${F}`>
  : ACC;
type CamelCase<S extends string> = ToCamelCase<Lowercase<S>>           // conver all chars to lower case first

type x = CamelCase<'FOOBAR'>
type y = CamelCase<'foo_bar_hello_world'>
/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<CamelCase<'foobar'>, 'foobar'>>,
  Expect<Equal<CamelCase<'FOOBAR'>, 'foobar'>>,
  Expect<Equal<CamelCase<'foo_bar'>, 'fooBar'>>,
  Expect<Equal<CamelCase<'foo_bar_hello_world'>, 'fooBarHelloWorld'>>,
  Expect<Equal<CamelCase<'HELLO_WORLD_WITH_TYPES'>, 'helloWorldWithTypes'>>,
  Expect<Equal<CamelCase<'-'>, '-'>>,
  Expect<Equal<CamelCase<''>, ''>>,
  Expect<Equal<CamelCase<'😎'>, '😎'>>,
]