Is it possible to create a meeting request for outlook with nodeJS?

For those still looking for an answer, here's how I managed to get the perfect solution for me. I used iCalToolkit to create a calendar object.

It's important to make sure all the relevant fields are set up (organizer and attendees with RSVP).

Initially I was using the Postmark API service to send my emails but this solution was only working by sending an ics.file attachment.

I switched to the Postmark SMTP service where you can embed the iCal data inside the message and for that I used nodemailer.

This is what it looks like :

        var icalToolkit = require('ical-toolkit');
        var postmark = require('postmark');
        var client = new postmark.Client('xxxxxxxKeyxxxxxxxxxxxx');
        var nodemailer = require('nodemailer');
        var smtpTransport = require('nodemailer-smtp-transport');

        //Create a iCal object
        var builder = icalToolkit.createIcsFileBuilder();
        builder.method = meeting.method;
        //Add the event data

        var icsFileContent = builder.toString();
        var smtpOptions = {
            host:'smtp.postmarkapp.com',
            port: 2525,
            secureConnection: true,
            auth:{
               user:'xxxxxxxKeyxxxxxxxxxxxx',
               pass:'xxxxxxxPassxxxxxxxxxxx'
            }
        };

        var transporter = nodemailer.createTransport(smtpTransport(smtpOptions));

        var mailOptions = {
            from: '[email protected]',
            to: meeting.events[0].attendees[i].email,
            subject: 'Meeting to attend',
            html: "Anything here",
            text: "Anything here",
            alternatives: [{
              contentType: 'text/calendar; charset="utf-8"; method=REQUEST',
              content: icsFileContent.toString()
            }]
        };

        //send mail with defined transport object 
        transporter.sendMail(mailOptions, function(error, info){
            if(error){
                console.log(error);
            }
            else{
                console.log('Message sent: ' + info.response);  
            }
        });

This sends a real meeting request with the Accept, decline and Reject button.

It's really unbelievable the amount of work you need to go through for such a trivial functionality and how all of this not well documented. Hope this helps.

Instead of using 'ical-generator', I used 'ical-toolkit' to build a calender invite event. Using this, the invite directly gets appended in the email instead of the attached .ics file object.

Here is a sample code:

const icalToolkit = require("ical-toolkit");

//Create a builder
var builder = icalToolkit.createIcsFileBuilder();
builder.method = "REQUEST"; // The method of the request that you want, could be REQUEST, PUBLISH, etc

//Add events
builder.events.push({
  start: new Date(2020, 09, 28, 10, 30),
  end: new Date(2020, 09, 28, 12, 30),
  timestamp: new Date(),
  summary: "My Event",
  uid: uuidv4(), // a random UUID
  categories: [{ name: "MEETING" }],
  attendees: [
    {
      rsvp: true,
      name: "Akarsh ****",
      email: "Akarsh **** <akarsh.***@abc.com>"
    },
    {
      rsvp: true,
      name: "**** RANA",
      email: "**** RANA <****[email protected]>"
    }
  ],
  organizer: {
    name: "A****a N****i",
    email: "A****a N****i <a****a.r.n****[email protected]>"
  }
});

//Try to build
var icsFileContent = builder.toString();

//Check if there was an error (Only required if yu configured to return error, else error will be thrown.)
if (icsFileContent instanceof Error) {
  console.log("Returned Error, you can also configure to throw errors!");
  //handle error
}

var mailOptions = { // Set the values you want. In the alternative section, set the calender file
            from: obj.from,
            to: obj.to,
            cc: obj.cc,
            subject: result.email.subject,
            html: result.email.html,
            text: result.email.text,
            alternatives: [
              {
                contentType: 'text/calendar; charset="utf-8"; method=REQUEST',
                content: icsFileContent.toString()
              }
            ]
          }

        //send mail with defined transport object 
        transporter.sendMail(mailOptions, function(error, info){
            if(error){
                console.log(error);
            }
            else{
                console.log('Message sent: ' + info.response);  
            }
        });

If you do not want to use smtp server approach in earlier accepted solution, you have Exchange focused solution available. Whats wrong in current accepted answer? it does not create a meeting in sender's Calendar, you do not have ownership of the meeting item for further modification by the sender Outlook/OWA.

here is code snippet in javascript using npm package ews-javascript-api

var ews = require("ews-javascript-api");
var credentials = require("../credentials");
ews.EwsLogging.DebugLogEnabled = false;

var exch = new ews.ExchangeService(ews.ExchangeVersion.Exchange2013);

exch.Credentials = new ews.ExchangeCredentials(credentials.userName, credentials.password);

exch.Url = new ews.Uri("https://outlook.office365.com/Ews/Exchange.asmx");

var appointment = new ews.Appointment(exch);

appointment.Subject = "Dentist Appointment";
appointment.Body = new ews.TextBody("The appointment is with Dr. Smith.");
appointment.Start = new ews.DateTime("20170502T130000");
appointment.End = appointment.Start.Add(1, "h");
appointment.Location = "Conf Room";
appointment.RequiredAttendees.Add("[email protected]");
appointment.RequiredAttendees.Add("[email protected]");
appointment.OptionalAttendees.Add("[email protected]");

appointment.Save(ews.SendInvitationsMode.SendToAllAndSaveCopy).then(function () {
    console.log("done - check email");
}, function (error) {
    console.log(error);
});