Extensible markup language.
Quaint is a markup language that's a bit similar to Markdown, but is more regular and easier to customize. Unfortunately the markup is poorly documented at the moment, but you can use it interactively here.
npm install quaint
var quaint = require("quaint"); quaint.toHTML("Hello _italic __[bold words]."); // ==> "Hello <i>italic</i> <b>bold words</b>"