Calling a function returns undefined

Question

I am trying to call this function in another js file. This function should return the msg subject which you see towards the last part of the code. It returns undefined.

How to call this function so it returns the msg subject and lets store it in a variable?

Import statement used is correct:

import {getGmailData} from '../../Generic/Gmail.js

For example: let subject = getGmailData()

  export async function getGmailData(){

     await getOauthClient().then(async auth=> {

      let gmail = google.gmail({
        version: 'v1',
        auth: auth
      });  

      // Only get the recent email - 'maxResults' parameter

        gmail.users.messages.list({userId: 'me', maxResults: 1}, async (err, response) => {
          if (err) {

            return console.log('The API returned an error: ' + err);
      
          }
  
        // Get the message id which we will need to retreive the actual message next.
        const message_id = response['data']['messages'][0]['id'];
        console.log("message id is:" +message_id)
  
        
        // Retreive the actual message using the message id
       
         gmail.users.messages.get({userId: 'me', 'id': message_id }, async (err, response) => {
            if (err) {
                return console.log('The API returned an error: ' + err);
            }
  
            // Access the email body content, like this...
           
              let message_raw = response.data.payload.parts[0].body.data;
              let data = message_raw;
              var buff = await  new Buffer.from(data, 'base64');
              var text = await buff.toString();
              //console.log("Email body is:" +text);
  
              //Access the email subject as per below code:
  
              let msgSubject = ''
              let  msgHeaders = response.data.payload.headers
              //let headers = msgHeaders
               for (let header of msgHeaders) {
                if (header.name === 'Subject') {
                   msgSubject = header.value;
                   console.log(msgSubject)
                   **return msgSubject**
                }
              }   
        });
      });
    });
  }

The `return` statement in the `async` arrow function you pass to `gmail.users.messages.get` belongs to that arrow function and not to the different async arrow function you pass to `getOauthClient().then` or to `getGmailData`. — Quentin, Aug 08 '23 at 12:50
you are only returning something inside an if? maybe that's the problem? — Chris G, Aug 08 '23 at 12:50
Okay then how do we make sure the msg subject is returned when we call this function from anywhere? — Sndeep, Aug 08 '23 at 12:54
You code would be easier to understand if you (a) Used [consistent indenting](https://beautifier.io/) (b) Learned how to format Stackoverflow questions so that *all* your code was marked as code and (c) Used `await` consistently instead of sometimes using `await` and sometimes using `.then()`. — Quentin, Aug 08 '23 at 12:54
@Sndeep — See the duplicate question about how to handle functions which provide their results to a callback function. — Quentin, Aug 08 '23 at 12:55

Calling a function returns undefined

0 Answers0