Nodejs - Refresh token (generate a 3-legged AccessToken) for Robot accounts

refreshMechanism.js

// To install:  > npm install node-fetch node-persist
// Notes: node-persist stores the refresh token data, into a text file on disk, so
//        if the server reboots, the refresh token is persisted.

const fetch = require('node-fetch');
const storage = require('node-persist');

const FORGEURL = `https://developer.api.autodesk.com`;


// This mechanism provides an Access Token to BIM360 APIs, as a standard user, not 2-legged.  
// It does this by using a 3-legged refreshToken to automatically generate a new AccessToken.

class RefreshMechanism {
    constructor() {
		this.newRefreshToken();
		setInterval(i => this.newRefreshToken(), (3600*1000)); //get new access token every hour	
	}


    async newRefreshToken() {
        await storage.init(); //init node-persist
	this.FORGE_KEY = `<enter your forge-key here>`;
        this.FORGE_SECRET = `<enter your forge-secret here>`;
        let refreshToken = await storage.getItem('refreshToken'); // get our last refresh token

        fetch(`${FORGEURL}/authentication/v1/refreshtoken`, {
            method: 'POST',
            body: `client_id=${this.FORGE_KEY}&client_secret=${this.FORGE_SECRET}&grant_type=refresh_token&refresh_token=${refreshToken}`,
            headers: { "Content-Type": 'application/x-www-form-urlencoded' },
        })
        .then(res => res.json())
        .then(res => {
            this.access_token = res.access_token;
            this.refresh_token = res.refresh_token;
            if (this.refresh_token)
                storage.setItem('refreshToken',this.refresh_token);
        });
}