[perlmonks.org Readability Enhancements] Make posts & code easier to read on perlmonks.org #UserScript

perlmonksReadabilityEnhancements.user.js

// ==UserScript==
// @name                 perlmonks.org Readability Enhancements
// @description	         Readability Enhancements for perlmonks.org
// @author               rjf89
// @include              http://perlmonks.org/*
// @include              https://perlmonks.org/*
// @include              http://*.perlmonks.org/*
// @include              https://*.perlmonks.org/*
// @include              http://www.perlmonks.org/*
// @include              https://www.perlmonks.org/*
// @include              http://*.www.perlmonks.org/*
// @include              https://*.www.perlmonks.org/*
// @require              http://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/highlight.min.js
// @resource theme       http://cdnjs.cloudflare.com/ajax/libs/highlight.js/9.12.0/styles/tomorrow-night.min.css
// @grant                GM_addStyle
// @grant                GM_getResourceText
// @run-at               document-start
// @version              0.1
// ==/UserScript==

const STYLE_TWEAKS = `
h3 { margin-bock-end: 0px; }
tr.titlebar { display: none; }
.hljs {
  font-size: 1.1em;
  font-family: SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}
`;

let concat = (previous, current) => [...previous, ...current];
let flatMap = (xs, fn) => xs.map(fn).reduce(concat, []);

(function () {
    'use strict'
    GM_addStyle(STYLE_TWEAKS);
    GM_addStyle(GM_getResourceText('theme'));
    function hlCode(elem) {
        elem.classList.add('language-perl');
        window.hljs.highlightBlock(elem);
    };

    function processCodeBlock(e) {
        if (e.classList && e.classList.contains('codetext') && !e.classList.contains('language-perl')) hlCode(e);
        else if (e.childElementCount > 0) [...e.getElementsByClassName('codetext')].forEach(hlCode);
    }

    var observer = new MutationObserver(function(ms) { flatMap(ms, m => m.addedNodes).forEach(processCodeBlock); });
    observer.observe(document, {childList: true, subtree: true});
})();

good job ,it works for me. thanks.