Plain Nodejs Microsoft Graph OAuth 2.0 client credentials grant flow

index.js

const https = require('https');
const querystring = require('querystring');

const form = {
    client_id: '<>',   // a guid
    client_secret: '<>', // an app secret
    scope: 'https://graph.microsoft.com/.default',
    grant_type: 'client_credentials'
};

const formStr = querystring.stringify(form);

const tenant = ''; // xxxx.onmicrosoft.com

const options = {
    method: 'POST',
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded',
        'Content-Length': Buffer.byteLength(formStr)
    }
};

const req = https.request(`https://login.microsoftonline.com/${tenant}/oauth2/v2.0/token`, options, (res) => {
    console.log('statusCode:', res.statusCode);
    console.log('headers:', res.headers);

    let responseData = '';

    res.on('data', (d) => {
        responseData += d;
    });

    res.on('end', () => {
        console.log(responseData);
    });

}).on('error', (e) => {
    console.error(e);
});

req.write(formStr);

req.end();