文字列Sに含まれる文字FromをToに一度だけ置き換える型Replace<S, From, To>を実装します。
例えば
type replaced = Replace<'types are fun!', 'fun', 'awesome'>; // expected to be 'types are awesome!'
import type { 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', 'bar', ''>, 'foobar'>>,
Expect<Equal<Replace<'foobarbar', 'bra', 'foo'>, 'foobarbar'>>,
Expect<Equal<Replace<'', '', ''>, ''>>,
]