使用字符代码获取字符串中单词的频率，JavaScript

function getWordFrequency(str) {
  // 将字符串转换为小写，并去除标点符号
  str = str.toLowerCase().replace(/[^\w\s]/g, '');

  // 将字符串按空格分割为单词数组
  const words = str.split(' ');

  // 创建一个对象来存储单词及其出现的频率
  const frequency = {};

  // 遍历单词数组，统计每个单词的频率
  for (let i = 0; i < words.length; i++) {
    const word = words[i];
    if (frequency[word]) {
      frequency[word]++;
    } else {
      frequency[word] = 1;
    }
  }

  return frequency;
}

// 示例用法
const str = "This is a test. This is only a test.";
const frequency = getWordFrequency(str);
console.log(frequency);