whatsapp-web.js is a WhatsApp client library for NodeJS that connects through the WhatsApp Web browser app. It uses Puppeteer to run a real instance of Whatsapp Web to avoid getting blocked.
remoteStorage.js is a JavaScript library for storing user data locally in the browser, as well as connecting to remoteStorage servers and syncing data across devices and applications. It is also capable of connecting and syncing data with a person’s Dropbox or Google Drive account (optional).