const input = "One two three"; let r = input.replace(/two/, '($`)'); console.log(r); // One (One ) three r = input.replace(/\w+/g, '($&)'); console.log(r); // (One) (two) (three) r = input.replace(/two/, "($')"); console.log(r); // One ( three) three r = input.replace(/two/, "($$)"); console.log(r); // One ($) three