得到'承诺{<pending> }' 使用 async-await 执行 tcp 客户端时的消息</pending>

Question

I am performing tcp client using telnet-client node module.

const Telnet = require('telnet-client')

async function wazuhRun(host) {
  let connection = new Telnet()
  let ErrCode = -1;

  let params = {
    host: host,
    port: 2345,
    negotiationMandatory: false,
    timeout: 1500
  }

  try {
  await connection.connect(params)
  ErrCode = 0;
  } catch(error) {
  ErrCode = -1;
  }
  return ErrCode;
}

const code = wazuhRun('linux345');
console.log(code);

On running above code, I am getting Promise { <pending> }

Please suggest what might be missing in my code

Answer 1

Since you're using it outside of a async function you need to treat it as a Promise:

wazuhRun('linux345').then((result) => console.log(result));

async functions are a syntatic sugar around Promises, they get translated into Promises which is why you get Promise pending.

If you were calling it from inside another async function you could use:

const code = await wazuhRun('linux345');

EDIT: About the null return, it could be that your function throws an error before your try/catch.

 wazuhRun('linux345')
    .then((result) => console.log(result))
    .catch((error) => console.log(error));

By adding a catch handler to your Promise you'll be able to see all errors thrown from within your async function.

Answer 2

Use wazuhRun('linux345').then() the it will work fine.

const Telnet = require('telnet-client')

async function wazuhRun(host) {
  let connection = new Telnet()
  let ErrCode = -1;

  let params = {
    host: host,
    port: 2345,
    negotiationMandatory: false,
    timeout: 1500
  }

  try {
  await connection.connect(params)
  ErrCode = 0;
  } catch(error) {
  ErrCode = -1;
  }
  return ErrCode;
}

wazuhRun('linux345').then(data => {
  console.log(data);
}).catch(err => {
  console.log(err);
})