Sample Node for obtaining an application token to call Microsoft Graph API

ad-application-token-for-graph-api.js

var request = require('request');
const MicrosoftGraph = require("@microsoft/microsoft-graph-client");

// required inputs
var tenant = '';   // tenant id
var clientId = ''; // application id
var secret = '';   // application password

// prepare http request
var url = 'https://login.microsoftonline.com/' + tenant + '/oauth2/v2.0/token';
var body = 'grant_type=client_credentials&client_id=' + clientId + '&scope=https%3A%2F%2Fgraph.microsoft.com%2F.default&client_secret=' + secret

const options = {
    url: url,
    body: body,
    headers: {
        'Content-Type': 'application/x-www-form-urlencoded'
    }
};

// Call the token API to get a token
request(options, handler);

// handle response and call graph
var handler = function (error, response, body) {
    if (!error && response.statusCode == 200) {
        var json = JSON.parse(body);
        var token = json.access_token;

        // TODO here you can do something with the token

        // e.g. test the token by calling graph api
        callGraphApi(token);
    } else {
        console.log(body);
    }
}

// make a call to graph to test the access token
var callGraphApi = function (token) {

    // Initialize Graph client
    const client = MicrosoftGraph.Client.init({
        defaultVersion: 'v1.0',
        debugLogging: true,
        authProvider: (done) => {
            done(null, token);
        }
    });

    // get sharepoint root
    client
        .api('/sites/root')
        .get()
        .then((res) => {
            console.log(res);
        }).catch((res) => {
            console.log(res);
        });
}