Let's Encrypt is "a free, automated, and open Certificate Authority." They provide free signed certificates as a trusted certificate authority. This tutorial walks through the process of installing certbot and requesting new certificates and renewing existing ones wit Let's Encrypt. If you are just looking to generate your own quick self-signed certificates, check out my tutorial on creating self-signed SSL certificates with OpenSSL.
There is a wget package available for Node.js that makes it really easy to integrate the convenience of wget in to a Node.js program. It is useful for downloading a file from any number of protocols. This example shows you how to download a file using wget in Node.js
These code snippets demonstrate how to access command line arguments for a Node.js program.
jQuery provide a convenient way to access elements using CSS selectors. Node.js has a package called Cheerio that allows us to make jQuery style code. The Request module can be used in tandem to provide the ability to perform an HTTP GET to fetch remote HTML documents. That is useful for web scraping.