Refer: Medium - Replace

Describe

Implement Replace<S, From, To> which replace the string From with To once in the given string S.

For example

code snippetCopytypescript
type replaced = Replace<'types are fun!', 'fun', 'awesome'> // expected to be 'types are awesome!'

Test Cases

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

type cases = [
  Expect<Equal<Replace<'foobar', 'bar', 'foo'>, 'foofoo'>>,
  Expect<Equal<Replace<'foobarbar', 'bar', 'foo'>, 'foofoobar'>>,
  Expect<Equal<Replace<'foobarbar', '', 'foo'>, 'foobarbar'>>,
  Expect<Equal<Replace<'foobarbar', 'bra', 'foo'>, 'foobarbar'>>,
  Expect<Equal<Replace<'', '', ''>, ''>>,
]

Solution

code snippetCopytypescript
type Replace<S extends string, From extends string, To extends string> = From extends ''
  ? S
  : S extends `${infer P}${From}${infer K}`
  ? `${P}${To}${K}`
  : S