使用"crypto“创建的函数不会返回我用它创建的bearerToken

const crypto = require('crypto');

function generateBearerToken(userId, secretKey, expiresIn) {
  const payload = {
    userId: userId,
    exp: Math.floor(Date.now() / 1000) + expiresIn
  };

  const header = {
    alg: 'HS256',
    typ: 'JWT'
  };

  const encodedHeader = Buffer.from(JSON.stringify(header)).toString('base64');
  const encodedPayload = Buffer.from(JSON.stringify(payload)).toString('base64');
  const signature = crypto.createHmac('sha256', secretKey)
                           .update(encodedHeader + '.' + encodedPayload)
                           .digest('base64');

  return encodedHeader + '.' + encodedPayload + '.' + signature;
}

const userId = '12345';
const secretKey = 'your-secret-key';
const expiresIn = 3600; // 1 hour

const bearerToken = generateBearerToken(userId, secretKey, expiresIn);
console.log(bearerToken);