Converting Plain Text To Encoded HTML With Vanilla JavaScript

When copying text from a website to your device’s clipboard, there’s a good chance that you will get the formatted HTML when pasting it. Some apps and operating systems have a “Paste Special” feature that will strip those tags out for you to maintain the current style, but what do you do if that’s unavailable?
Same goes for converting plain text into formatted HTML. One of the closest ways we can convert plain text into HTML is writing in Markdown as an abstraction.