在Javascript中替换正则表达式匹配的第n个实例

function replaceNthMatch(input, regex, n, replacement) {
  let count = 0;
  const re = new RegExp(regex.source, regex.flags + 'g');
  return input.replace(re, (match, ...args) => {
    count++;
    if (count === n) {
      return replacement;
    }
    return match;
  });
}

const input = "The quick brown fox jumps over the lazy dog.";
const regex = /fox/g;
const n = 1;
const replacement = "cat";

const result = replaceNthMatch(input, regex, n, replacement);
console.log(result); // "The quick brown cat jumps over the lazy dog."