replace() 方法返回一个新字符串，其中一个、多个或所有匹配的 pattern 被替换为 replacement。pattern 可以是字符串或 RegExp，replacement 可以是字符串或一个在每次匹配时调用的函数。如果 pattern 是字符串，则只会替换第一个匹配项。原始的字符串不会改变。

const paragraph = "I think Ruth's dog is cuter than your dog!";

console.log(paragraph.replace("Ruth's", 'my'));
// Expected output: "I think my dog is cuter than your dog!"

const regex = /Dog/i;
console.log(paragraph.replace(regex, 'ferret'));
// Expected output: "I think Ruth's ferret is cuter than your dog!"