如何找出子字符串在给定字符串中出现的次数(包括连接)？

function countOccurrences(mainString, subString) {
  let count = 0;
  let position = mainString.indexOf(subString);
  while (position !== -1) {
    count++;
    position = mainString.indexOf(subString, position + 1);
  }
  return count;
}

const mainString = "abababa";
const subString = "aba";
const occurrences = countOccurrences(mainString, subString);
console.log(occurrences);  // 输出：2

function countOccurrences(mainString, subString) {
  const escapedSubString = subString.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
  const regex = new RegExp(escapedSubString, 'g');
  const matches = mainString.match(regex);
  return matches ? matches.length : 0;
}

const mainString = "abababa";
const subString = "aba";
const occurrences = countOccurrences(mainString, subString);
console.log(occurrences);  // 输出：2