Javascript variable = function() -> undefined

Asked Jul 31 '18 at 11:03

Active Jul 31 '18 at 11:55

Viewed 86 times

When I run this code the log file name will be 'undefined'. the checkfile return the correct file name, but the filename variable won't be equal with that.

const logger = async () => {
  filename = await checkFile();
  openFile();
}

const checkFile = async () => {
  originfn = "xyservice_" + await datetime.date() + ".log";

  fs.access(`logs/${originfn}`, fs.constants.F_OK, (err) => {
    //console.log(`logs/${origfn} ${err ? 'does not exist' : 'exists'}`);
    if (err) {

      return originfn;
    } else {

      return originfn + ".2";
    }
  });
}

const openFile = async () => {
  fs.appendFile(`logs/${filename}`, await time() + `Logging system 
started...in file logs/${filename}`, function(err) {
    if (err) console.log(err);

    console.log('Log file created...');
  });

  return;
}

Then how is this code working? I do not understand. Whats the diffs?

const permParser = async (perms) => {

let permissions = {}

//general code

return permissions;
}

I call like this
await permParser(permtopars)

edited Jul 31 '18 at 11:55

asked Jul 31 '18 at 11:03

mszabolcs

Well... you definitely do not understand how to work with async/await functions, do you? – Artem Jul 31 '18 at 11:05
Yeah, I just got into it. – mszabolcs Jul 31 '18 at 11:06
I don't think you've got the understanding of how callbacks work, you can't `return` from async callbacks. – James Jul 31 '18 at 11:07
Keyword `await` should be placed in front of async functions, such as `fs.access(...)` & `fs.appendFile(...)` – Artem Jul 31 '18 at 11:07
5

Your function doesn’t return anything, hence the default return value (‘undefined’). – An0num0us Jul 31 '18 at 11:08

Javascript variable = function() -> undefined

0 Answers0