nodejs ssh连接使用Promise返回错误的值

npm install ssh2

const { Client } = require('ssh2');

function connectSSH(host, port, username, password) {
  return new Promise((resolve, reject) => {
    const conn = new Client();
    conn.on('ready', () => {
      resolve(conn);
    }).on('error', (err) => {
      reject(err);
    }).connect({
      host: host,
      port: port,
      username: username,
      password: password
    });
  });
}

connectSSH('hostname', 22, 'username', 'password')
  .then((conn) => {
    // 连接成功，可以执行相关操作
    conn.exec('command', (err, stream) => {
      if (err) throw err;
      stream.on('close', (code, signal) => {
        conn.end();
      }).on('data', (data) => {
        console.log('stdout: ' + data);
      }).stderr.on('data', (data) => {
        console.log('stderr: ' + data);
      });
    });
  })
  .catch((err) => {
    // 连接失败，处理错误
    console.error(err);
  });