type _ToCamel<S extends string, A extends string = ""> =
  S extends `${infer L}_${infer R}`
  ? `${Capitalize<L>}${_ToCamel<R>}`
  : Capitalize<S>
type SnakeToCamel<S extends string> = Uncapitalize<_ToCamel<S>>
type CamelizeArray<T extends unknown[]> =
  T extends [infer L, ...infer R]
  ? [Camelize<L>, ...CamelizeArray<R>]
  : []
type Camelize<T> =
  T extends Record<string, unknown>
  ? { [P in keyof T as P extends string ? SnakeToCamel<P> : never]: Camelize<T[P]> }
  : T extends unknown[]
  ? CamelizeArray<T>
  : T

import type { Equal, Expect } from '@type-challenges/utils'

type cases = [
  Expect<Equal<
  Camelize<{
    some_prop: string
    prop: { another_prop: string }
    array: [{ snake_case: string }]
  }>,
  {
    someProp: string
    prop: { anotherProp: string }
    array: [{ snakeCase: string }]
  }
  >>,
]