有没有办法让我的javascript随机字符串中的字母字符大写？

function randomStringWithUpperCase(length) {
  let result = '';
  const characters = 'abcdefghijklmnopqrstuvwxyz';
  const charactersLength = characters.length;

  for (let i = 0; i < length; i++) {
    // 随机获取一个字母
    let randomChar = characters.charAt(Math.floor(Math.random() * charactersLength));
    
    // 将字母转换为大写
    randomChar = randomChar.toUpperCase();
    
    result += randomChar;
  }

  return result;
}

// 调用函数生成长度为10的随机字符串
const randomStr = randomStringWithUpperCase(10);
console.log(randomStr);