如何在async / await格式中处理多个args的回调函数？

Question

In shelljs, the exec function has 3 arguments in callback (err, stdout, stderr) . When using this in async/await by promisify(shelljs.exec) , I'm not able to catch the stderr ?

const { promisify } = require('util'),
  shellExec = promisify(shelljs.exec);

....

// in the function

try {
 variableName = await shellExec('some valid shell command', {});

 return variableName;
}
catch (err) {
  console.log(err);
}

If shelljs exec return code 0 ie valid response it works fine, but when the the command is invalid, it returns 1.

I'm not able to get the stderr .

Answer 1

I am assuming you want the value of stderr to output while also using async/await. Something like this might be of use:

var shelljs = require('shelljs');

async function promiseExec(input) {
  return new Promise((resolve, reject) => {
    let { err, stdout, stderr } = shelljs.exec(input);
    shelljs.exit(1);
    if(stdout === "") reject(stderr);
    resolve(stdout);
  })
}

async function main () {
  let result = await promiseExec('dir');
  console.log(result);
}

main();