使用Javascript查找字符串中最常见的单词？

function findMostCommonWord(str) {
  // 将字符串转换为单词数组
  const words = str.toLowerCase().split(/\W+/);
  // 创建一个空对象，用于存储每个单词的出现次数
  const wordCounts = {};
  // 遍历单词数组，将每个单词添加到对象中，并统计出现次数
  words.forEach(word => {
    if (word) {
      wordCounts[word] = (wordCounts[word] || 0) + 1;
    }
  });
  // 初始化最常见单词及其出现次数
  let mostCommonWord = '';
  let maxCount = 0;
  // 遍历对象，找到出现次数最高的单词
  for (const word in wordCounts) {
    if (wordCounts[word] > maxCount) {
      mostCommonWord = word;
      maxCount = wordCounts[word];
    }
  }
  return mostCommonWord;
}

// 示例
const str = 'This is a test string. This string is used to test the findMostCommonWord function.';
console.log(findMostCommonWord(str)); // 输出 "is"