Refer: Medium - Replace All

Describe

Implement ReplaceAll<S, From, To> which replace the all the substring From with To in the given string S.

For example

code snippetCopytypescript
type replaced = ReplaceAll<'t y p e s', ' ', ''> // expected to be 'types'

Test Cases

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

type cases = [
  Expect<Equal<ReplaceAll<'foobar', 'bar', 'foo'>, 'foofoo'>>,
  Expect<Equal<ReplaceAll<'foobar', 'bag', 'foo'>, 'foobar'>>,
  Expect<Equal<ReplaceAll<'foobarbar', 'bar', 'foo'>, 'foofoofoo'>>,
  Expect<Equal<ReplaceAll<'t y p e s', ' ', ''>, 'types'>>,
  Expect<Equal<ReplaceAll<'foobarbar', '', 'foo'>, 'foobarbar'>>,
  Expect<Equal<ReplaceAll<'barfoo', 'bar', 'foo'>, 'foofoo'>>,
  Expect<Equal<ReplaceAll<'foobarfoobar', 'ob', 'b'>, 'fobarfobar'>>,
  Expect<Equal<ReplaceAll<'foboorfoboar', 'bo', 'b'>, 'foborfobar'>>,
  Expect<Equal<ReplaceAll<'', '', ''>, ''>>,
]

Solution

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