getCssElmClasses.js

function getCssElmClasses() {
  const a = [...document.styleSheets]
    .map((b) => [...b.cssRules])
    .flat()
    .map((b) => b instanceof CSSMediaRule ? [...b.cssRules] : [b])
    .flat()
    .map((b) => b.selectorText)
    .filter((b) => b)
    .map((b) => b.split(","))
    .flat()
    .map((b) => b.trim())
    .filter((b) => b.match(/^\./))
    .map((b) => b.replace(/^\.([a-zA-Z0-9_-]*).*$/, "$1"))
    .map((b) => `${b.replace(/-./g, (c) => c.substr(1).toUpperCase())} = class ${JSON.stringify(b)}`)
  return [...new Set(a).keys()].join("\n")
}
document.write(getCssElmClasses().replace(/\n/g, "<br>"))