type _ = Replace<`a,b,c`, ['a','b'], 'x'>; // 'x,x,c' type _ = Replace<`hogepiyo`, ['hoge'], ''>; // 'piyo' type _ = Replace<`a,b,c`, [], 'x'>; // 'a,b,c'

type Replace< S extends string, Froms extends string[], To extends string > = Froms extends [infer H extends string, ...infer Tail extends string[]] ? Replace<Replace1<S, H, To>, Tail, To> : S; // prettier-ignore type Replace1< S extends string, From extends string, To extends string > = From extends '' ? S : S extends `${infer F}${From}${infer L}` ? `${F}${To}${Replace1<L, From, To>}` : S;