Q:

Modern Oauth2 authentication for sending mails using Nodemailer nodejs

I am using nodemailer to send email in my nodejs application.
var payload = { auth: 
               {
                user: smtpuser,
                pass: smtppass
               },
                to : toAddr,
                from  : emailfrom,
                cc : ccAddr,
                subject : subject,
                html    : content,
                attachments: attachments
              };

var transporter = nodemailer.createTransport(
                   { host: payload.host || 'smtp.office365.com', // Office 365 server
                     port: payload.port || 587,     // secure SMTP
                     secure:payload.secure || false, // false for TLS - as a boolean not string - but the default is false so just remove this completely
                     auth: payload.auth,
                     debug: true,
                     tls: payload.tls || {ciphers: 'SSLv3'}
                   });

transporter.sendMail(payload, function (error, info) {
                if (error) {
                    return console.log(error);
                }
                updateMessage(updatedMsg);
            });

I started getting this error: 

Error: Invalid log in: 535 5.7.3 Authentication unsuccessful [SN4PR0601CA0002.namprd06.prod.outlook.com]

It seems my team has now disabled basic authentication. 
I need to implement modern authentication(Oauth2) to be able to send mails via nodemailer using the outlook id.
Does anyone have any idea about this?
What configuration(code) changes will that require ?

A:

I'd suggest that you use Microsoft Graph to send emails. There's an easy to use REST API that works greatly with OAuth. 
Please find below some links to help you build this out quickly. 
https://docs.microsoft.com/en-us/graph/api/user-sendmail?view=graph-rest-1.0&tabs=http
https://docs.microsoft.com/en-us/graph/auth/auth-concepts?view=graph-rest-1.0
https://docs.microsoft.com/en-us/graph/tutorials/node?view=graph-rest-1.0

