从长字符串正则表达式中获取匹配子字符串

const longString = "This is a long string with some matching substrings.";
const regex = /is/g; // 匹配所有的 "is"

let match;
while ((match = regex.exec(longString)) !== null) {
  const matchedSubstring = match[0];
  console.log(matchedSubstring);
}

is
is

const longString = "This is a long string with some matching substrings.";
const regex = /is/; // 匹配第一个 "is"

const match = longString.match(regex);
const matchedSubstring = match[0];
console.log(matchedSubstring);

is