☰

SE Preview on hover

Shows preview of the linked questions/answers on hover

当前为 2019-08-28 提交的版本，查看 最新版本。

  1. // ==UserScript==
  2. // @name           SE Preview on hover
  3. // @description    Shows preview of the linked questions/answers on hover
  4. // @version        1.0.3
  5. // @author         wOxxOm
  6. // @namespace      wOxxOm.scripts
  7. // @license        MIT License
  8.  
  9. // please use only matches for the previewable targets and make sure the domain
  10. // is extractable via [-.\w] so that it starts with . like .stackoverflow.com
  11. // @match          *://*.stackoverflow.com/*
  12. // @match          *://*.superuser.com/*
  13. // @match          *://*.serverfault.com/*
  14. // @match          *://*.askubuntu.com/*
  15. // @match          *://*.stackapps.com/*
  16. // @match          *://*.mathoverflow.net/*
  17. // @match          *://*.stackexchange.com/*
  18.  
  19. // please use only includes for the container sites
  20. // @include        *://www.google.com/search*/
  21. // @include        /https?:\/\/(www\.)?google(\.com?)?(\.\w\w)?\/(webhp|q|.*?[?#]q=|search).*/
  22. // @include        *://*.bing.com/*
  23. // @include        *://*.yahoo.com/*
  24. // @include        /https?:\/\/(\w+\.)*yahoo.(com|\w\w(\.\w\w)?)\/.*/
  25.  
  26. // @require        https://greasyfork.org/scripts/27531/code/LZStringUnsafe.js
  27. // @require        https://greasyfork.org/scripts/375977/code/StackOverflow-code-prettify-bundle.js
  28.  
  29. // @grant          GM_addStyle
  30. // @grant          GM_xmlhttpRequest
  31. // @grant          GM_getValue
  32. // @grant          GM_setValue
  33. // @grant          GM_getResourceText
  34.  
  35. // @connect        stackoverflow.com
  36. // @connect        superuser.com
  37. // @connect        serverfault.com
  38. // @connect        askubuntu.com
  39. // @connect        stackapps.com
  40. // @connect        mathoverflow.net
  41. // @connect        stackexchange.com
  42. // @connect        sstatic.net
  43. // @connect        gravatar.com
  44. // @connect        imgur.com
  45. // @connect        self
  46.  
  47. // @run-at         document-end
  48. // @noframes
  49. // ==/UserScript==
  50.  
  51. /* global GM_info GM_addStyle GM_xmlhttpRequest GM_getValue GM_setValue GM_getResourceText */
  52. /* global initPrettyPrint LZStringUnsafe */
  53. 'use strict';
  54.  
  55. Promise.resolve().then(() => {
  56.   Detector.init();
  57.   Security.init();
  58.   Urler.init();
  59.   Cache.init();
  60.  
  61. //  for (const obj of [Target, Target.prototype, Preview]) {
  62. //    for (const [name, {writable, value}] of Object.entries(Object.getOwnPropertyDescriptors(obj))) {
  63. //      if (writable &&
  64. //          typeof value === 'function' &&
  65. //          value !== Target.createHoverable &&
  66. //          name !== 'constructor') {
  67. //        console.debug('hooking', Target.name, name);
  68. //        Object.defineProperty(obj, name, {
  69. //          value(...args) {
  70. //            console.debug(name, [this, ...args]);
  71. //            return value.apply(this, args);
  72. //          },
  73. //          writable: true,
  74. //        });
  75. //      }
  76. //    }
  77. //  }
  78. });
  79.  
  80. const PREVIEW_DELAY = 200;
  81. const AUTOHIDE_DELAY = 1000;
  82. const BUSY_CURSOR_DELAY = 300;
  83. // 1 minute for the recently active posts, scales up logarithmically
  84. const CACHE_DURATION = 60e3;
  85.  
  86. const PADDING = 24;
  87. const QUESTION_WIDTH = 677; // unconstrained width of a question's .post_text
  88. const ANSWER_WIDTH = 657; // unconstrained width of an answer's .post_text
  89. const WIDTH = Math.max(QUESTION_WIDTH, ANSWER_WIDTH) + PADDING * 2;
  90. const BORDER = 8;
  91. const TOP_BORDER = 24;
  92. const MIN_HEIGHT = 200;
  93. const COLORS = {
  94.   question: {
  95.     back: '#5894d8',
  96.     fore: '#265184',
  97.     foreInv: '#fff',
  98.   },
  99.   answer: {
  100.     back: '#70c350',
  101.     fore: '#3f7722',
  102.     foreInv: '#fff',
  103.   },
  104.   deleted: {
  105.     back: '#cd9898',
  106.     fore: '#b56767',
  107.     foreInv: '#fff',
  108.   },
  109.   closed: {
  110.     back: '#ffce5d',
  111.     fore: '#c28800',
  112.     foreInv: '#fff',
  113.   },
  114. };
  115. const ID = 'SEpreview';
  116. const EXPANDO = Symbol(ID);
  117.  
  118. const pv = {
  119.   /** @type {Target} */
  120.   target: null,
  121.   /** @type {Element} */
  122.   _frame: null,
  123.   /** @type {Element} */
  124.   get frame() {
  125.     if (!this._frame)
  126.       Preview.init();
  127.     if (!document.contains(this._frame))
  128.       document.body.appendChild(this._frame);
  129.     return this._frame;
  130.   },
  131.   set frame(element) {
  132.     this._frame = element;
  133.     return element;
  134.   },
  135.   /** @type {Post} */
  136.   post: {},
  137.   hover: {x: 0, y: 0},
  138.   stylesOverride: '',
  139. };
  140.  
  141. class Detector {
  142.  
  143.   static init() {
  144.     const sites = GM_info.script.matches.map(m => m.match(/[-.\w]+/)[0]);
  145.     const rxsSites = 'https?://(\\w*\\.)*(' +
  146.       GM_info.script.matches
  147.         .map(m => m.match(/^.*?\/\/\W*(\w.*?)\//)[1].replace(/\./g, '\\.'))
  148.         .join('|') +
  149.       ')/';
  150.     Detector.rxPreviewableSite = new RegExp(rxsSites);
  151.     Detector.rxPreviewablePost = new RegExp(rxsSites + '(questions|q|a|posts/comments)/\\d+');
  152.     Detector.pageUrls = getBaseUrls(location, Detector.rxPreviewablePost);
  153.     Detector.isStackExchangePage = Detector.rxPreviewableSite.test(location);
  154.  
  155.     const {
  156.       rxPreviewablePost,
  157.       isStackExchangePage: isSE,
  158.       pageUrls: {base, baseShort},
  159.     } = Detector;
  160.  
  161.     // array of target elements accumulated in mutation observer
  162.     // cleared in attachHoverListener
  163.     const moQueue = [];
  164.  
  165.     onMutation([{
  166.       addedNodes: [document.body],
  167.     }]);
  168.  
  169.     new MutationObserver(onMutation)
  170.       .observe(document.body, {
  171.         childList: true,
  172.         subtree: true,
  173.       });
  174.  
  175.     Detector.init = true;
  176.  
  177.     function onMutation(mutations) {
  178.       /* let, const, iterators are still too slow for an observer in 2018 Dec */
  179.       var alreadyScheduled = moQueue.length > 0;
  180.       for (var i = 0, ml = mutations.length; i < ml; i++) {
  181.         var addedNodes = mutations[i].addedNodes;
  182.         for (var j = 0, nl = addedNodes.length; j < nl; j++) {
  183.           var n = addedNodes[j];
  184.           // skip if not Node.ELEMENT_NODE
  185.           if (n.nodeType !== 1)
  186.             continue;
  187.           if (n.localName === 'a') {
  188.             moQueue.push(n);
  189.             continue;
  190.           }
  191.           var k, len, targets;
  192.           // not using ..spreading since there could be 100k links for all we know
  193.           // and that might exceed JS engine stack limit which can be pretty low
  194.           targets = n.getElementsByTagName('a');
  195.           for (k = 0, len = targets.length; k < len; k++)
  196.             moQueue.push(targets[k]);
  197.           if (!isSE)
  198.             continue;
  199.           if (n.classList.contains('question-summary')) {
  200.             moQueue.push(...n.getElementsByClassName('answered'));
  201.             moQueue.push(...n.getElementsByClassName('answered-accepted'));
  202.             continue;
  203.           }
  204.           targets = n.getElementsByClassName('question-summary');
  205.           for (k = 0, len = targets.length; k < len; k++) {
  206.             var el = targets[k];
  207.             moQueue.push(...el.getElementsByClassName('answered'));
  208.             moQueue.push(...el.getElementsByClassName('answered-accepted'));
  209.           }
  210.         }
  211.       }
  212.       if (!alreadyScheduled && moQueue.length)
  213.         setTimeout(hoverize);
  214.     }
  215.  
  216.     function hoverize() {
  217.       /* let, const, iterators are still too slow for an observer in 2018 Dec */
  218.       for (var i = 0, len = moQueue.length; i < len; i++) {
  219.         var el = moQueue[i];
  220.         if (el[EXPANDO] instanceof Target)
  221.           continue;
  222.         if (el.localName === 'a') {
  223.           if (isSE && el.classList.contains('js-share-link'))
  224.             continue;
  225.           var previewable = isPreviewable(el) ||
  226.                             !isSE && isEmbeddedUrlPreviewable(el);
  227.           if (!previewable)
  228.             continue;
  229.           var url = Urler.makeHttps(el.href);
  230.           if (url.startsWith(base) || url.startsWith(baseShort))
  231.             continue;
  232.         }
  233.         Target.createHoverable(el);
  234.       }
  235.       moQueue.length = 0;
  236.     }
  237.  
  238.     function isPreviewable(a) {
  239.       var href = false;
  240.       var host = '.' + a.hostname;
  241.       var hostLen = host.length;
  242.       for (var i = 0, len = sites.length; i < len; i++) {
  243.         var stackSite = sites[i];
  244.         if (host[hostLen - stackSite.length] === '.' &&
  245.             host.endsWith(stackSite) &&
  246.             rxPreviewablePost.test(href || (href = a.href)))
  247.           return true;
  248.       }
  249.     }
  250.  
  251.     function isEmbeddedUrlPreviewable(a) {
  252.       var url = a.href;
  253.       var i = url.indexOf('http', 1);
  254.       if (i < 0)
  255.         return false;
  256.       i = (
  257.         url.indexOf('http://', i) + 1 ||
  258.         url.indexOf('https://', i) + 1 ||
  259.         url.indexOf('http%3A%2F%2F', i) + 1 ||
  260.         url.indexOf('https%3A%2F%2F', i) + 1
  261.       ) - 1;
  262.       if (i < 0)
  263.         return false;
  264.       var j = url.indexOf('&', i);
  265.       var embeddedUrl = url.slice(i, j > 0 ? j : undefined);
  266.       return rxPreviewablePost.test(embeddedUrl);
  267.     }
  268.  
  269.     function getBaseUrls(url, rx) {
  270.       if (!rx.test(url))
  271.         return {};
  272.       const base = Urler.makeHttps(RegExp.lastMatch);
  273.       return {
  274.         base,
  275.         baseShort: base.replace('/questions/', '/q/'),
  276.       };
  277.     }
  278.   }
  279. }
  280.  
  281. /**
  282.  * @property {Element} element
  283.  * @property {Boolean} isLink
  284.  * @property {String}  url
  285.  * @property {Number}  timer
  286.  * @property {Number}  timerCursor
  287.  * @property {String}  savedCursor
  288.  */
  289. class Target {
  290.  
  291.   /** @param {Element} el */
  292.   static createHoverable(el) {
  293.     const target = new Target(el);
  294.     Object.defineProperty(el, EXPANDO, {value: target});
  295.     el.removeAttribute('title');
  296.     el.addEventListener('mouseover', Target._onMouseOver);
  297.     return target;
  298.   }
  299.  
  300.   /** @param {Element} el */
  301.   constructor(el) {
  302.     this.element = el;
  303.     this.isLink = el.localName === 'a';
  304.   }
  305.  
  306.   release() {
  307.     $.off('mousemove', this.element, Target._onMove);
  308.     $.off('mouseout', this.element, Target._onHoverEnd);
  309.     $.off('mousedown', this.element, Target._onHoverEnd);
  310.  
  311.     for (const k in this) {
  312.       if (k.startsWith('timer') && this[k] >= 1) {
  313.         clearTimeout(this[k]);
  314.         this[k] = 0;
  315.       }
  316.     }
  317.     BusyCursor.hide(this);
  318.     pv.target = null;
  319.   }
  320.  
  321.   get url() {
  322.     const el = this.element;
  323.     if (this.isLink)
  324.       return el.href;
  325.     const a = $('a', el.closest('.question-summary'));
  326.     if (a)
  327.       return a.href;
  328.   }
  329.  
  330.   /** @param {MouseEvent} e */
  331.   static _onMouseOver(e) {
  332.     if (Util.hasKeyModifiers(e))
  333.       return;
  334.     const self = /** @type {Target} */ this[EXPANDO];
  335.     if (self === Preview.target && Preview.shown() ||
  336.         self === pv.target)
  337.       return;
  338.  
  339.     if (pv.target)
  340.       pv.target.release();
  341.     pv.target = self;
  342.  
  343.     pv.hover.x = e.pageX;
  344.     pv.hover.y = e.pageY;
  345.  
  346.     $.on('mousemove', this, Target._onMove);
  347.     $.on('mouseout', this, Target._onHoverEnd);
  348.     $.on('mousedown', this, Target._onHoverEnd);
  349.  
  350.     Target._restartTimer(self);
  351.   }
  352.  
  353.   /** @param {MouseEvent} e */
  354.   static _onHoverEnd(e) {
  355.     if (e.type === 'mouseout' && e.target !== this)
  356.       return;
  357.     const self = /** @type {Target} */ this[EXPANDO];
  358.     if (pv.xhr && pv.target === self) {
  359.       pv.xhr.abort();
  360.       pv.xhr = null;
  361.     }
  362.     self.release();
  363.     self.timer = setTimeout(Target._onAbortTimer, AUTOHIDE_DELAY, self);
  364.   }
  365.  
  366.   /** @param {MouseEvent} e */
  367.   static _onMove(e) {
  368.     const stoppedMoving =
  369.       Math.abs(pv.hover.x - e.pageX) < 2 &&
  370.       Math.abs(pv.hover.y - e.pageY) < 2;
  371.     if (stoppedMoving) {
  372.       pv.hover.x = e.pageX;
  373.       pv.hover.y = e.pageY;
  374.       Target._restartTimer(this[EXPANDO]);
  375.     }
  376.   }
  377.  
  378.   /** @param {Target} self */
  379.   static _restartTimer(self) {
  380.     if (self.timer)
  381.       clearTimeout(self.timer);
  382.     self.timer = setTimeout(Target._onTimer, PREVIEW_DELAY, self);
  383.   }
  384.  
  385.   /** @param {Target} self */
  386.   static _onTimer(self) {
  387.     self.timer = 0;
  388.     const el = self.element;
  389.     if (!el.matches(':hover')) {
  390.       self.release();
  391.       return;
  392.     }
  393.     $.off('mousemove', el, Target._onMove);
  394.  
  395.     if (self.url)
  396.       Preview.start(self);
  397.   }
  398.  
  399.   /** @param {Target} self */
  400.   static _onAbortTimer(self) {
  401.     if ((self === pv.target || self === Preview.target) &&
  402.         pv.frame && !pv.frame.matches(':hover')) {
  403.       pv.target = null;
  404.       Preview.hide({fade: true});
  405.     }
  406.   }
  407. }
  408.  
  409.  
  410. class BusyCursor {
  411.  
  412.   /** @param {Target} target */
  413.   static schedule(target) {
  414.     target.timerCursor = setTimeout(BusyCursor._onTimer, BUSY_CURSOR_DELAY, target);
  415.   }
  416.  
  417.   /** @param {Target} target */
  418.   static hide(target) {
  419.     if (target.timerCursor) {
  420.       clearTimeout(target.timerCursor);
  421.       target.timerCursor = 0;
  422.     }
  423.     const style = target.element.style;
  424.     if (style.cursor === 'wait')
  425.       style.cursor = target.savedCursor;
  426.   }
  427.  
  428.   /** @param {Target} target */
  429.   static _onTimer(target) {
  430.     target.timerCursor = 0;
  431.     target.savedCursor = target.element.style.cursor;
  432.     $.setStyle(target.element, ['cursor', 'wait']);
  433.   }
  434. }
  435.  
  436.  
  437. class Preview {
  438.  
  439.   static init() {
  440.     pv.frame = $.create(`#${ID}`, {parent: document.body});
  441.     pv.shadow = pv.frame.attachShadow({mode: 'open'});
  442.     pv.body = $.create(`body#${ID}-body`, {parent: pv.shadow});
  443.  
  444.     const WRAP_AROUND = '(or wrap around to the question)';
  445.     const TITLE_PREV = 'Previous answer\n' + WRAP_AROUND;
  446.     const TITLE_NEXT = 'Next answer\n' + WRAP_AROUND;
  447.     const TITLE_ENTER = 'Return to the question\n(Enter was Return initially)';
  448.  
  449.     pv.answersTitle =
  450.       $.create(`#${ID}-answers-title`, [
  451.         'Answers:',
  452.         $.create('p', [
  453.           'Use ',
  454.           $.create('b', {title: TITLE_PREV}),
  455.           $.create('b', {title: TITLE_NEXT, attributes: {mirrored: ''}}),
  456.           $.create('label', {title: TITLE_ENTER}, 'Enter'),
  457.           ' to switch entries',
  458.         ]),
  459.       ]);
  460.  
  461.     $.on('keydown', pv.frame, Preview.onKey);
  462.     $.on('keyup', pv.frame, Util.consumeEsc);
  463.  
  464.     $.on('mouseover', pv.body, ScrollLock.enable);
  465.     $.on('click', pv.body, Preview.onClick);
  466.  
  467.     Sizer.init();
  468.     Styles.init();
  469.     Preview.init = true;
  470.   }
  471.  
  472.   /** @param {Target} target */
  473.   static async start(target) {
  474.     Preview.target = target;
  475.  
  476.     if (!Security.checked)
  477.       Security.check();
  478.  
  479.     const {url} = target;
  480.  
  481.     let data = Cache.read(url);
  482.     if (data) {
  483.       const r = await Urler.get(url, {method: 'HEAD'});
  484.       const postTime = Util.getResponseDate(r.responseHeaders);
  485.       if (postTime >= data.time)
  486.         data = null;
  487.     }
  488.  
  489.     if (!data) {
  490.       BusyCursor.schedule(target);
  491.       const {finalUrl, responseText: html} = await Urler.get(target.url);
  492.       data = {finalUrl, html, unsaved: true};
  493.       BusyCursor.hide(target);
  494.     }
  495.  
  496.     data.url = url;
  497.     data.showAnswer = !target.isLink;
  498.  
  499.     if (!Preview.prepare(data))
  500.       Preview.target = null;
  501.     else if (data.unsaved && data.lastActivity >= 1)
  502.       Preview.save(data);
  503.   }
  504.  
  505.   static save({url, finalUrl, html, lastActivity}) {
  506.     const inactiveDays = Math.max(0, (Date.now() - lastActivity) / (24 * 3600e3));
  507.     const cacheDuration = CACHE_DURATION * Math.pow(Math.log(inactiveDays + 1) + 1, 2);
  508.     setTimeout(Cache.write, 1000, {url, finalUrl, html, cacheDuration});
  509.   }
  510.  
  511.   // data is mutated: its lastActivity property is assigned!
  512.   static prepare(data) {
  513.     const {finalUrl, html, showAnswer, doc = Util.parseHtml(html)} = data;
  514.  
  515.     if (!doc || !doc.head)
  516.       return Util.error('no HEAD in the document received for', finalUrl);
  517.  
  518.     if (!$('base', doc))
  519.       $.create('base', {href: finalUrl, parent: doc.head});
  520.  
  521.     let answerId;
  522.     if (showAnswer) {
  523.       const el = $('[id^="answer-"]', doc);
  524.       answerId = el && el.id.match(/\d+/)[0];
  525.     } else {
  526.       answerId = finalUrl.match(/questions\/\d+\/[^/]+\/(\d+)|$/)[1];
  527.     }
  528.     const selector = answerId ? '#answer-' + answerId : '#question';
  529.     const core = $(selector + ' .post-text', doc);
  530.     if (!core)
  531.       return Util.error('No parsable post found', doc);
  532.  
  533.     const isQuestion = !answerId;
  534.     const status = isQuestion && !$('.question-status', core) ?
  535.       $('.question-status', doc) :
  536.       null;
  537.     const isClosed = Boolean($(
  538.       '.question-originals-of-duplicate,' +
  539.       '.close-as-off-topic-status-list,' +
  540.       '.close-status-suffix',
  541.       doc));
  542.     const isDeleted = Boolean(core.closest('.deleted-answer'));
  543.     const type = [
  544.       isQuestion && 'question' || 'answer',
  545.       isDeleted && 'deleted',
  546.       isClosed && 'closed',
  547.     ].filter(Boolean).join(' ');
  548.     const answers = $.all('.answer', doc);
  549.     const comments = $(`${selector} .comments`, doc);
  550.     const remainingCommentsElement = $('[data-remaining-comments-count]', comments);
  551.     const remainingComments = Number(remainingCommentsElement.dataset.remainingCommentsCount);
  552.     const lastActivity = Util.tryCatch(Util.extractTime, $('.lastactivity-link', doc)) ||
  553.                          Date.now();
  554.     Object.assign(pv, {
  555.       finalUrl,
  556.       finalUrlOfQuestion: Urler.makeCacheable(finalUrl),
  557.     });
  558.     /** @typedef Post
  559.      * @property {Document}  doc
  560.      * @property {String}    html
  561.      * @property {String}    selector
  562.      * @property {String}    type
  563.      * @property {String}    id
  564.      * @property {String}    title
  565.      * @property {Boolean}   isQuestion
  566.      * @property {Boolean}   isDeleted
  567.      * @property {Number}    lastActivity
  568.      * @property {Number}    numAnswers
  569.      * @property {Element}   core
  570.      * @property {Element}   comments
  571.      * @property {Element[]} answers
  572.      * @property {Element[]} renderParts
  573.      */
  574.     Object.assign(pv.post, {
  575.       doc,
  576.       html,
  577.       core,
  578.       selector,
  579.       answers,
  580.       comments,
  581.       type,
  582.       isQuestion,
  583.       isDeleted,
  584.       lastActivity,
  585.       id: isQuestion ? Urler.getFirstNumber(finalUrl) : answerId,
  586.       title: $('meta[property="og:title"]', doc).content,
  587.       numAnswers: answers.length,
  588.       renderParts: [
  589.         status,
  590.         // including the parent so the right CSS kicks in
  591.         core.parentElement,
  592.         comments.parentElement,
  593.         remainingComments && $(`${selector} .js-show-link.comments-link`, doc),
  594.       ],
  595.     });
  596.  
  597.     $.remove('script', doc);
  598.     // remove the comment actions block
  599.     $.remove('[id^="comments-link-"]', doc);
  600.  
  601.     Promise.all([
  602.       pv.frame,
  603.       Preview.addStyles(),
  604.       Security.ready(),
  605.     ]).then(Preview.show);
  606.  
  607.     data.lastActivity = lastActivity;
  608.     return true;
  609.   }
  610.  
  611.   static show() {
  612.     Render.all();
  613.  
  614.     const style = getComputedStyle(pv.frame);
  615.     if (style.opacity !== '1' || style.display !== 'block') {
  616.       $.setStyle(pv.frame, ['display', 'block']);
  617.       setTimeout($.setStyle, 0, pv.frame, ['opacity', '1']);
  618.     }
  619.  
  620.     pv.parts.focus();
  621.   }
  622.  
  623.   static hide({fade = false} = {}) {
  624.     if (Preview.target) {
  625.       Preview.target.release();
  626.       Preview.target = null;
  627.     }
  628.  
  629.     pv.body.onmouseover = null;
  630.     pv.body.onclick = null;
  631.     pv.body.onkeydown = null;
  632.  
  633.     if (fade) {
  634.       Util.fadeOut(pv.frame)
  635.         .then(Preview.eraseBoxIfHidden);
  636.     } else {
  637.       $.setStyle(pv.frame,
  638.         ['opacity', '0'],
  639.         ['display', 'none']);
  640.       Preview.eraseBoxIfHidden();
  641.     }
  642.   }
  643.  
  644.   static shown() {
  645.     return pv.frame.style.opacity === '1';
  646.   }
  647.  
  648.   /** @param {KeyboardEvent} e */
  649.   static onKey(e) {
  650.     switch (e.key) {
  651.       case 'Escape':
  652.         Preview.hide({fade: true});
  653.         break;
  654.       case 'ArrowUp':
  655.       case 'PageUp':
  656.         if (pv.parts.scrollTop)
  657.           return;
  658.         break;
  659.       case 'ArrowDown':
  660.       case 'PageDown': {
  661.         const {scrollTop: t, clientHeight: h, scrollHeight} = pv.parts;
  662.         if (t + h < scrollHeight)
  663.           return;
  664.         break;
  665.       }
  666.       case 'ArrowLeft':
  667.       case 'ArrowRight': {
  668.         if (!pv.post.numAnswers)
  669.           return;
  670.         // current is 0 if isQuestion, 1 is the first answer
  671.         const answers = $.all(`#${ID}-answers a`);
  672.         const current = pv.post.numAnswers ?
  673.           answers.indexOf($('.SEpreviewed')) + 1 :
  674.           pv.post.isQuestion ? 0 : 1;
  675.         const num = pv.post.numAnswers + 1;
  676.         const dir = e.key === 'ArrowLeft' ? -1 : 1;
  677.         const toShow = (current + dir + num) % num;
  678.         const a = toShow ? answers[toShow - 1] : $(`#${ID}-title`);
  679.         a.click();
  680.         break;
  681.       }
  682.       case 'Enter':
  683.         if (pv.post.isQuestion)
  684.           return;
  685.         $(`#${ID}-title`).click();
  686.         break;
  687.       default:
  688.         return;
  689.     }
  690.     e.preventDefault();
  691.   }
  692.  
  693.   /** @param {MouseEvent} e */
  694.   static onClick(e) {
  695.     if (e.target.id === `${ID}-close`) {
  696.       Preview.hide();
  697.       return;
  698.     }
  699.  
  700.     const link = e.target.closest('a');
  701.     if (!link)
  702.       return;
  703.  
  704.     if (link.matches('.js-show-link.comments-link')) {
  705.       Util.fadeOut(link, 0.5);
  706.       Preview.loadComments();
  707.       e.preventDefault();
  708.       return;
  709.     }
  710.  
  711.     if (e.button ||
  712.         Util.hasKeyModifiers(e) ||
  713.         !link.matches('.SEpreviewable')) {
  714.       link.target = '_blank';
  715.       return;
  716.     }
  717.  
  718.     e.preventDefault();
  719.  
  720.     const {doc} = pv.post;
  721.     if (link.id === `${ID}-title`)
  722.       Preview.prepare({doc, finalUrl: pv.finalUrlOfQuestion});
  723.     else if (link.matches(`#${ID}-answers a`))
  724.       Preview.prepare({doc, finalUrl: pv.finalUrlOfQuestion + '/' + Urler.getFirstNumber(link)});
  725.     else
  726.       Preview.start(new Target(link));
  727.   }
  728.  
  729.   static eraseBoxIfHidden() {
  730.     if (!Preview.shown())
  731.       pv.body.textContent = '';
  732.   }
  733.  
  734.   static setHeight(height) {
  735.     const currentHeight = pv.frame.clientHeight;
  736.     const borderHeight = pv.frame.offsetHeight - currentHeight;
  737.     const newHeight = Math.max(MIN_HEIGHT, Math.min(innerHeight - borderHeight, height));
  738.     if (newHeight !== currentHeight)
  739.       $.setStyle(pv.frame, ['height', newHeight + 'px']);
  740.   }
  741.  
  742.   static async addStyles() {
  743.     let last = $.create(`style#${ID}-styles.${Styles.REUSABLE}`, {
  744.       textContent: pv.stylesOverride,
  745.       before: pv.shadow.firstChild,
  746.     });
  747.  
  748.     if (!pv.styles)
  749.       pv.styles = new Map();
  750.  
  751.     const toDownload = [];
  752.     const sourceElements = $.all('link[rel="stylesheet"], style', pv.post.doc);
  753.  
  754.     for (const {href, textContent, localName} of sourceElements) {
  755.       const isLink = localName === 'link';
  756.       const id = ID + '-style-' + (isLink ? href : await Util.sha256(textContent));
  757.       const el = pv.styles.get(id);
  758.       if (!el && isLink)
  759.         toDownload.push(Urler.get({url: href, context: id}));
  760.       last = $.create('style', {
  761.         id,
  762.         className: Styles.REUSABLE,
  763.         textContent: isLink ? $.text(el) : textContent,
  764.         after: last,
  765.       });
  766.       pv.styles.set(id, last);
  767.     }
  768.  
  769.     const downloaded = await Promise.all(toDownload);
  770.  
  771.     for (const {responseText, context: id} of downloaded)
  772.       pv.shadow.getElementById(id).textContent = responseText;
  773.   }
  774.  
  775.   static async loadComments() {
  776.     const list = $(`#${pv.post.comments.id} .comments-list`);
  777.     const url = new URL(pv.finalUrl).origin +
  778.                 '/posts/' + pv.post.comments.id.match(/\d+/)[0] + '/comments';
  779.     list.innerHTML = (await Urler.get(url)).responseText;
  780.  
  781.     const oldIds = new Set([...list.children].map(e => e.id));
  782.     for (const cmt of list.children) {
  783.       if (!oldIds.has(cmt.id))
  784.         cmt.classList.add('new-comment-highlight');
  785.     }
  786.  
  787.     $.setStyle(list.closest('.comments'), ['display', 'block']);
  788.     Render.previewableLinks(list);
  789.     Render.hoverableUsers(list);
  790.   }
  791. }
  792.  
  793.  
  794. class Render {
  795.  
  796.   static all() {
  797.     pv.frame.classList.toggle(`${ID}-hasAnswerShelf`, pv.post.numAnswers > 0);
  798.     pv.frame.setAttribute(`${ID}-type`, pv.post.type);
  799.     pv.body.setAttribute(`${ID}-type`, pv.post.type);
  800.  
  801.     $.create(`a#${ID}-title.SEpreviewable`, {
  802.       href: pv.finalUrlOfQuestion,
  803.       textContent: pv.post.title,
  804.       parent: pv.body,
  805.     });
  806.  
  807.     $.create(`#${ID}-close`, {
  808.       title: 'Or press Esc key while the preview is focused (also when just shown)',
  809.       parent: pv.body,
  810.     });
  811.  
  812.     $.create(`#${ID}-meta`, {
  813.       parent: pv.body,
  814.       onmousedown: Sizer.onMouseDown,
  815.       children: [
  816.         Render._votes(),
  817.         pv.post.isQuestion
  818.           ? Render._questionMeta()
  819.           : Render._answerMeta(),
  820.       ],
  821.     });
  822.  
  823.     Render.previewableLinks(pv.post.doc);
  824.  
  825.     pv.post.answerShelf = pv.post.answers.map(Render._answer);
  826.     if (Security.noImages)
  827.       Security.embedImages(...pv.post.renderParts);
  828.  
  829.     pv.parts = $.create(`#${ID}-parts`, {
  830.       className: pv.post.isDeleted ? 'deleted-answer' : '',
  831.       tabIndex: 0,
  832.       scrollTop: 0,
  833.       parent: pv.body,
  834.       children: pv.post.renderParts,
  835.     });
  836.  
  837.     Render.hoverableUsers(pv.parts);
  838.  
  839.     if (pv.post.numAnswers) {
  840.       $.create(`#${ID}-answers`, {parent: pv.body}, [
  841.         pv.answersTitle,
  842.         pv.post.answerShelf,
  843.       ]);
  844.     } else {
  845.       $.remove(`#${ID}-answers`, pv.body);
  846.     }
  847.  
  848.     // delinkify/remove non-functional items in post-menu
  849.     $.remove('.js-share-link, .flag-post-link', pv.body);
  850.     for (const a of $.all('.post-menu a:not(.edit-post)')) {
  851.       if (a.children.length)
  852.         $.create('span', {before: a}, a.childNodes);
  853.       a.remove();
  854.     }
  855.  
  856.     // add a timeline link
  857.     $.appendChildren($('.post-menu'), [
  858.       $.create('span.lsep'),
  859.       $.create('a', {href: `/posts/${pv.post.id}/timeline`}, 'timeline'),
  860.     ]);
  861.  
  862.     // prettify code blocks
  863.     const codeBlocks = $.all('pre code');
  864.     if (codeBlocks.length) {
  865.       codeBlocks.forEach(e =>
  866.         e.parentElement.classList.add('prettyprint'));
  867.       if (!pv.prettify)
  868.         initPrettyPrint((pv.prettify = {}));
  869.       if (typeof pv.prettify.prettyPrint === 'function')
  870.         pv.prettify.prettyPrint(null, pv.body);
  871.     }
  872.  
  873.     const leftovers = $.all('style, link, script, .post-menu .lsep + .lsep');
  874.     for (const el of leftovers) {
  875.       if (el.classList.contains(Styles.REUSABLE))
  876.         el.classList.remove(Styles.REUSABLE);
  877.       else
  878.         el.remove();
  879.     }
  880.  
  881.     pv.post.html = null;
  882.     pv.post.core = null;
  883.     pv.post.renderParts = null;
  884.     pv.post.answers = null;
  885.     pv.post.answerShelf = null;
  886.   }
  887.  
  888.   /** @param {Element} container */
  889.   static previewableLinks(container) {
  890.     for (const a of $.all('a:not(.SEpreviewable)', container)) {
  891.       let href = a.getAttribute('href');
  892.       if (!href)
  893.         continue;
  894.       if (!href.includes('://')) {
  895.         href = a.href;
  896.         a.setAttribute('href', href);
  897.       }
  898.       if (Detector.rxPreviewablePost.test(href)) {
  899.         a.removeAttribute('title');
  900.         a.classList.add('SEpreviewable');
  901.       }
  902.     }
  903.   }
  904.  
  905.   /** @param {Element} container */
  906.   static hoverableUsers(container) {
  907.     for (const a of $.all('a[href*="/users/"]', container)) {
  908.       if (Detector.rxPreviewableSite.test(a.href) &&
  909.           a.pathname.match(/^\/users\/\d+/)) {
  910.         a.onmouseover = UserCard.onUserLinkHovered;
  911.         a.classList.add(`${ID}-userLink`);
  912.       }
  913.     }
  914.   }
  915.  
  916.   /** @param {Element} el */
  917.   static _answer(el) {
  918.     const shortUrl = $('.js-share-link', el).href.replace(/(\d+)\/\d+/, '$1');
  919.     const extraClasses =
  920.       (el.matches(pv.post.selector) ? ' SEpreviewed' : '') +
  921.       (el.matches('.deleted-answer') ? ' deleted-answer' : '') +
  922.       (el.matches('.accepted-answer') ? ` ${ID}-accepted` : '');
  923.     const author = $('.post-signature:last-child', el);
  924.     const title =
  925.       $.text('.user-details a', author) +
  926.       ' (rep ' +
  927.       $.text('.reputation-score', author) +
  928.       ')\n' +
  929.       $.text('.user-action-time', author);
  930.     let gravatar = $('img, .anonymous-gravatar, .community-wiki', author);
  931.     if (gravatar && Security.noImages)
  932.       Security.embedImages(gravatar);
  933.     if (gravatar && gravatar.src)
  934.       gravatar = $.create('img', {src: gravatar.src});
  935.     const a = $.create('a', {
  936.       href: shortUrl,
  937.       title: title,
  938.       className: 'SEpreviewable' + extraClasses,
  939.       textContent: $.text('.js-vote-count', el).replace(/^0$/, '\xA0') + ' ',
  940.       children: gravatar,
  941.     });
  942.     return [a, ' '];
  943.   }
  944.  
  945.   static _votes() {
  946.     const votes = $.text('.js-vote-count', pv.post.core.closest('.post-layout'));
  947.     if (Number(votes))
  948.       return $.create('b', `${votes} vote${Math.abs(votes) >= 2 ? 's' : ''}`);
  949.   }
  950.   static _questionMeta() {
  951.     return $.all('#qinfo tr', pv.post.doc)
  952.       .map(row => $.all('.label-key', row).map($.text).join(' '))
  953.       .join(', ')
  954.       .replace(/^((.+?) (.+?), .+?), .+? \3$/, '$1');
  955.   }
  956.  
  957.   static _answerMeta() {
  958.     return $.all('.user-action-time', pv.post.core.closest('.answer'))
  959.       .reverse()
  960.       .map($.text)
  961.       .join(', ');
  962.   }
  963. }
  964.  
  965.  
  966. class UserCard {
  967.  
  968.   _fadeIn() {
  969.     this._retakeId(this);
  970.     $.setStyle(this.element,
  971.       ['opacity', '0'],
  972.       ['display', 'block']);
  973.     this.timer = setTimeout(() => {
  974.       if (this.timer)
  975.         $.setStyle(this.element, ['opacity', '1']);
  976.     });
  977.   }
  978.  
  979.   _retakeId() {
  980.     if (this.element.id !== 'user-menu') {
  981.       const oldCard = $('#user-menu');
  982.       if (oldCard)
  983.         oldCard.id = oldCard.style.display = '';
  984.       this.element.id = 'user-menu';
  985.     }
  986.   }
  987.  
  988.   // 'this' is the hoverable link enclosing the user's name/avatar
  989.   static onUserLinkHovered() {
  990.     clearTimeout(this[EXPANDO]);
  991.     this[EXPANDO] = setTimeout(UserCard._show, PREVIEW_DELAY * 2, this);
  992.   }
  993.  
  994.   /** @param {HTMLAnchorElement} a */
  995.   static async _show(a) {
  996.     if (!a.matches(':hover'))
  997.       return;
  998.     const el = a.nextElementSibling;
  999.     const card = el && el.matches(`.${ID}-userCard`) && el[EXPANDO] ||
  1000.                  await UserCard._create(a);
  1001.     card._fadeIn();
  1002.   }
  1003.  
  1004.   /** @param {HTMLAnchorElement} a */
  1005.   static async _create(a) {
  1006.     const url = a.origin + '/users/user-info/' + Urler.getFirstNumber(a);
  1007.     let {html} = Cache.read(url) || {};
  1008.     if (!html) {
  1009.       html = (await Urler.get(url)).responseText;
  1010.       Cache.write({url, html, cacheDuration: CACHE_DURATION * 100});
  1011.     }
  1012.  
  1013.     const dom = Util.parseHtml(html);
  1014.     if (Security.noImages)
  1015.       Security.embedImages(dom);
  1016.  
  1017.     const b = a.getBoundingClientRect();
  1018.     const pb = pv.parts.getBoundingClientRect();
  1019.     const left = Math.min(b.left - 20, pb.right - 350) - pb.left + 'px';
  1020.     const isClipped = b.bottom + 100 > pb.bottom;
  1021.  
  1022.     const el = $.create(`#user-menu-tmp.${ID}-userCard`, {
  1023.       attributes: {
  1024.         style: `left: ${left} !important;` +
  1025.                (isClipped ? 'margin-top: -5rem !important;' : ''),
  1026.       },
  1027.       onmouseout: UserCard._onMouseOut,
  1028.       children: dom.body.children,
  1029.       after: a,
  1030.     });
  1031.  
  1032.     const card = new UserCard(el);
  1033.     Object.defineProperty(el, EXPANDO, {value: card});
  1034.     card.element = el;
  1035.     return card;
  1036.   }
  1037.  
  1038.   /** @param {MouseEvent} e */
  1039.   static _onMouseOut(e) {
  1040.     if (this.matches(':hover') ||
  1041.         this.style.opacity === '0' /* fading out already */)
  1042.       return;
  1043.  
  1044.     const self = /** @type {UserCard} */ this[EXPANDO];
  1045.     clearTimeout(self.timer);
  1046.     self.timer = 0;
  1047.  
  1048.     Util.fadeOut(this);
  1049.   }
  1050. }
  1051.  
  1052.  
  1053. class Sizer {
  1054.  
  1055.   static init() {
  1056.     Preview.setHeight(GM_getValue('height', innerHeight / 3) >> 0);
  1057.   }
  1058.  
  1059.   /** @param {MouseEvent} e */
  1060.   static onMouseDown(e) {
  1061.     if (e.button !== 0 || Util.hasKeyModifiers(e))
  1062.       return;
  1063.     Sizer._heightDelta = innerHeight - e.clientY - pv.frame.clientHeight;
  1064.     $.on('mousemove', document, Sizer._onMouseMove);
  1065.     $.on('mouseup', document, Sizer._onMouseUp);
  1066.   }
  1067.  
  1068.   /** @param {MouseEvent} e */
  1069.   static _onMouseMove(e) {
  1070.     Preview.setHeight(innerHeight - e.clientY - Sizer._heightDelta);
  1071.     getSelection().removeAllRanges();
  1072.   }
  1073.  
  1074.   /** @param {MouseEvent} e */
  1075.   static _onMouseUp(e) {
  1076.     GM_setValue('height', pv.frame.clientHeight);
  1077.     $.off('mouseup', document, Sizer._onMouseUp);
  1078.     $.off('mousemove', document, Sizer._onMouseMove);
  1079.   }
  1080. }
  1081.  
  1082.  
  1083. class ScrollLock {
  1084.  
  1085.   static enable() {
  1086.     if (ScrollLock.active)
  1087.       return;
  1088.     ScrollLock.active = true;
  1089.     ScrollLock.x = scrollX;
  1090.     ScrollLock.y = scrollY;
  1091.     $.on('mouseover', document.body, ScrollLock._onMouseOver);
  1092.     $.on('scroll', document, ScrollLock._onScroll);
  1093.   }
  1094.  
  1095.   static disable() {
  1096.     ScrollLock.active = false;
  1097.     $.off('mouseover', document.body, ScrollLock._onMouseOver);
  1098.     $.off('scroll', document, ScrollLock._onScroll);
  1099.   }
  1100.  
  1101.   static _onMouseOver() {
  1102.     if (ScrollLock.active)
  1103.       ScrollLock.disable();
  1104.   }
  1105.  
  1106.   static _onScroll() {
  1107.     scrollTo(ScrollLock.x, ScrollLock.y);
  1108.   }
  1109. }
  1110.  
  1111.  
  1112. class Security {
  1113.  
  1114.   static init() {
  1115.     if (Detector.isStackExchangePage) {
  1116.       Security.checked = true;
  1117.       Security.check = null;
  1118.     }
  1119.     Security.init = true;
  1120.   }
  1121.  
  1122.   static async check() {
  1123.     Security.noImages = false;
  1124.     Security._resolveOnReady = [];
  1125.     Security._imageCache = new Map();
  1126.  
  1127.     const {headers} = await fetch(location.href, {
  1128.       method: 'HEAD',
  1129.       cache: 'force-cache',
  1130.       mode: 'same-origin',
  1131.       credentials: 'same-origin',
  1132.     });
  1133.     const csp = headers.get('Content-Security-Policy');
  1134.     const imgSrc = /(?:^|[\s;])img-src\s+([^;]+)/i.test(csp) && RegExp.$1.trim();
  1135.     if (imgSrc)
  1136.       Security.noImages = !/(^\s)(\*|https?:)(\s|$)/.test(imgSrc);
  1137.  
  1138.     Security._resolveOnReady.forEach(fn => fn());
  1139.     Security._resolveOnReady = null;
  1140.     Security.checked = true;
  1141.     Security.check = null;
  1142.   }
  1143.  
  1144.   /** @return Promise<void> */
  1145.   static ready() {
  1146.     return Security.checked ?
  1147.       Promise.resolve() :
  1148.       new Promise(done => Security._resolveOnReady.push(done));
  1149.   }
  1150.  
  1151.   static embedImages(...containers) {
  1152.     for (const container of containers) {
  1153.       if (!container)
  1154.         continue;
  1155.       if (Util.isIterable(container)) {
  1156.         Security.embedImages(...container);
  1157.         continue;
  1158.       }
  1159.       if (container.localName === 'img') {
  1160.         Security._embedImage(container);
  1161.         continue;
  1162.       }
  1163.       for (const img of container.getElementsByTagName('img'))
  1164.         Security._embedImage(img);
  1165.     }
  1166.   }
  1167.  
  1168.   static _embedImage(img) {
  1169.     const src = img.src;
  1170.     if (!src || src.startsWith('data:'))
  1171.       return;
  1172.     const data = Security._imageCache.get(src);
  1173.     const alreadyFetching = Array.isArray(data);
  1174.     if (alreadyFetching) {
  1175.       data.push(img);
  1176.     } else if (data) {
  1177.       img.src = data;
  1178.       return;
  1179.     } else {
  1180.       Security._imageCache.set(src, [img]);
  1181.       Security._fetchImage(src);
  1182.     }
  1183.     $.setStyle(img, ['visibility', 'hidden']);
  1184.     img.dataset.src = src;
  1185.     img.removeAttribute('src');
  1186.   }
  1187.  
  1188.   static async _fetchImage(src) {
  1189.     const r = await Urler.get({url: src, responseType: 'blob'});
  1190.     const type = Util.getResponseMimeType(r.responseHeaders);
  1191.     const blob = r.response;
  1192.     const blobType = blob.type;
  1193.     let dataUri = await Util.blobToBase64(blob);
  1194.     if (blobType !== type)
  1195.       dataUri = 'data:' + type + dataUri.slice(dataUri.indexOf(';'));
  1196.  
  1197.     const images = Security._imageCache.get(src);
  1198.     Security._imageCache.set(src, dataUri);
  1199.  
  1200.     let detached = false;
  1201.     for (const el of images) {
  1202.       el.src = dataUri;
  1203.       el.style.removeProperty('visibility');
  1204.       if (!detached && el.ownerDocument !== document)
  1205.         detached = true;
  1206.     }
  1207.  
  1208.     if (detached) {
  1209.       for (const el of $.all(`img[data-src="${src}"]`)) {
  1210.         el.src = dataUri;
  1211.         el.style.removeProperty('visibility');
  1212.       }
  1213.     }
  1214.   }
  1215. }
  1216.  
  1217.  
  1218. class Cache {
  1219.  
  1220.   static init() {
  1221.     Cache.timers = new Map();
  1222.     setTimeout(Cache._cleanup, 10e3);
  1223.   }
  1224.  
  1225.   static read(url) {
  1226.     const keyUrl = Urler.makeCacheable(url);
  1227.     const [time, expires, finalUrl = url] = (localStorage[keyUrl] || '').split('\t');
  1228.     const keyFinalUrl = Urler.makeCacheable(finalUrl);
  1229.     return expires > Date.now() && {
  1230.       time,
  1231.       finalUrl,
  1232.       html: LZStringUnsafe.decompressFromUTF16(localStorage[keyFinalUrl + '\thtml']),
  1233.     };
  1234.   }
  1235.  
  1236.   // standard keyUrl = time,expiry
  1237.   //          keyUrl\thtml = html
  1238.   // redirected keyUrl = time,expiry,finalUrl
  1239.   //            keyFinalUrl = time,expiry
  1240.   //            keyFinalUrl\thtml = html
  1241.   static write({url, finalUrl, html, cacheDuration = CACHE_DURATION}) {
  1242.  
  1243.     cacheDuration = Math.max(CACHE_DURATION, Math.min(0x7FFF0000, cacheDuration >> 0));
  1244.     finalUrl = (finalUrl || url).replace(/[?#].*/, '');
  1245.  
  1246.     const keyUrl = Urler.makeCacheable(url);
  1247.     const keyFinalUrl = Urler.makeCacheable(finalUrl);
  1248.     const lz = LZStringUnsafe.compressToUTF16(html);
  1249.  
  1250.     if (!Util.tryCatch(Cache._writeRaw, keyFinalUrl + '\thtml', lz)) {
  1251.       Cache._cleanup({aggressive: true});
  1252.       if (!Util.tryCatch(Cache._writeRaw, keyFinalUrl + '\thtml', lz))
  1253.         return Util.error('localStorage write error');
  1254.     }
  1255.  
  1256.     const time = Date.now();
  1257.     const expiry = time + cacheDuration;
  1258.     localStorage[keyFinalUrl] = time + '\t' + expiry;
  1259.     if (keyUrl !== keyFinalUrl)
  1260.       localStorage[keyUrl] = time + '\t' + expiry + '\t' + finalUrl;
  1261.  
  1262.     const t = setTimeout(Cache._delete, cacheDuration + 1000,
  1263.       keyUrl,
  1264.       keyFinalUrl,
  1265.       keyFinalUrl + '\thtml');
  1266.  
  1267.     for (const url of [keyUrl, keyFinalUrl]) {
  1268.       clearTimeout(Cache.timers.get(url));
  1269.       Cache.timers.set(url, t);
  1270.     }
  1271.   }
  1272.  
  1273.   static _writeRaw(k, v) {
  1274.     localStorage[k] = v;
  1275.     return true;
  1276.   }
  1277.  
  1278.   static _delete(...keys) {
  1279.     for (const k of keys) {
  1280.       delete localStorage[k];
  1281.       Cache.timers.delete(k);
  1282.     }
  1283.   }
  1284.  
  1285.   static _cleanup({aggressive = false} = {}) {
  1286.     for (const k in localStorage) {
  1287.       if ((k.startsWith('http://') || k.startsWith('https://')) &&
  1288.           !k.includes('\t')) {
  1289.         const [, expires, url] = (localStorage[k] || '').split('\t');
  1290.         if (Number(expires) > Date.now() && !aggressive)
  1291.           break;
  1292.         if (url) {
  1293.           delete localStorage[url];
  1294.           Cache.timers.delete(url);
  1295.         }
  1296.         delete localStorage[(url || k) + '\thtml'];
  1297.         delete localStorage[k];
  1298.         Cache.timers.delete(k);
  1299.       }
  1300.     }
  1301.   }
  1302. }
  1303.  
  1304.  
  1305. class Urler {
  1306.  
  1307.   static init() {
  1308.     Urler.xhr = null;
  1309.     Urler.xhrNoSSL = new Set();
  1310.     Urler.init = true;
  1311.   }
  1312.  
  1313.   static getFirstNumber(url) {
  1314.     if (typeof url === 'string')
  1315.       url = new URL(url);
  1316.     return url.pathname.match(/\/(\d+)/)[1];
  1317.   }
  1318.  
  1319.   static makeHttps(url) {
  1320.     if (!url)
  1321.       return '';
  1322.     if (url.startsWith('http:'))
  1323.       return 'https:' + url.slice(5);
  1324.     return url;
  1325.   }
  1326.  
  1327.   // strips queries and hashes and anything after the main part
  1328.   // https://site/questions/NNNNNN/title/
  1329.   static makeCacheable(url) {
  1330.     return url
  1331.       .replace(/(\/q(?:uestions)?\/\d+\/[^/]+).*/, '$1')
  1332.       .replace(/(\/a(?:nswers)?\/\d+).*/, '$1')
  1333.       .replace(/[?#].*$/, '');
  1334.   }
  1335.  
  1336.   static get(options) {
  1337.     if (!options.url)
  1338.       options = {url: options, method: 'GET'};
  1339.     if (!options.method)
  1340.       options = Object.assign({method: 'GET'}, options);
  1341.  
  1342.     let url = options.url;
  1343.     const hostname = new URL(url).hostname;
  1344.  
  1345.     if (Urler.xhrNoSSL.has(hostname)) {
  1346.       url = url.replace(/^https/, 'http');
  1347.     } else {
  1348.       url = Urler.makeHttps(url);
  1349.       const _onerror = options.onerror;
  1350.       options.onerror = () => {
  1351.         options.onerror = _onerror;
  1352.         options.url = url.replace(/^https/, 'http');
  1353.         Urler.xhrNoSSL.add(hostname);
  1354.         return Urler.get(options);
  1355.       };
  1356.     }
  1357.  
  1358.     return new Promise(resolve => {
  1359.       let xhr;
  1360.       options.onload = r => {
  1361.         if (pv.xhr === xhr)
  1362.           pv.xhr = null;
  1363.         resolve(r);
  1364.       };
  1365.       options.url = url;
  1366.       xhr = pv.xhr = GM_xmlhttpRequest(options);
  1367.     });
  1368.   }
  1369. }
  1370.  
  1371.  
  1372. class Util {
  1373.  
  1374.   static tryCatch(fn, ...args) {
  1375.     try {
  1376.       return fn(...args);
  1377.     } catch (e) {}
  1378.   }
  1379.  
  1380.   static isIterable(o) {
  1381.     return typeof o === 'object' && Symbol.iterator in o;
  1382.   }
  1383.  
  1384.   static parseHtml(html) {
  1385.     if (!Util.parser)
  1386.       Util.parser = new DOMParser();
  1387.     return Util.parser.parseFromString(html, 'text/html');
  1388.   }
  1389.  
  1390.   static extractTime(element) {
  1391.     return new Date(element.title).getTime();
  1392.   }
  1393.  
  1394.   static getResponseMimeType(headers) {
  1395.     return headers.match(/^\s*content-type:\s*(.*)|$/mi)[1] ||
  1396.            'image/png';
  1397.   }
  1398.  
  1399.   static getResponseDate(headers) {
  1400.     try {
  1401.       return new Date(headers.match(/^\s*date:\s*(.*)/mi)[1]);
  1402.     } catch (e) {}
  1403.   }
  1404.  
  1405.   static blobToBase64(blob) {
  1406.     return new Promise((resolve, reject) => {
  1407.       const reader = new FileReader();
  1408.       reader.onerror = reject;
  1409.       reader.onload = e => resolve(e.target.result);
  1410.       reader.readAsDataURL(blob);
  1411.     });
  1412.   }
  1413.  
  1414.   static async sha256(str) {
  1415.     if (!pv.utf8encoder)
  1416.       pv.utf8encoder = new TextEncoder('utf-8');
  1417.     const buf = await crypto.subtle.digest('SHA-256', pv.utf8encoder.encode(str));
  1418.     const blob = new Blob([buf]);
  1419.     const url = await Util.blobToBase64(blob);
  1420.     return url.slice(url.indexOf(',') + 1);
  1421.   }
  1422.  
  1423.   /** @param {KeyboardEvent} e */
  1424.   static hasKeyModifiers(e) {
  1425.     return e.ctrlKey || e.altKey || e.shiftKey || e.metaKey;
  1426.   }
  1427.  
  1428.   static fadeOut(el, transition) {
  1429.     return new Promise(resolve => {
  1430.       if (transition) {
  1431.         if (typeof transition === 'number')
  1432.           transition = `opacity ${transition}s ease-in-out`;
  1433.         $.setStyle(el, ['transition', transition]);
  1434.         setTimeout(doFadeOut);
  1435.       } else {
  1436.         doFadeOut();
  1437.       }
  1438.       function doFadeOut() {
  1439.         $.setStyle(el, ['opacity', '0']);
  1440.         $.on('transitionend', el, done);
  1441.         $.on('visibilitychange', el, done);
  1442.       }
  1443.       function done() {
  1444.         $.off('transitionend', el, done);
  1445.         $.off('visibilitychange', el, done);
  1446.         if (el.style.opacity === '0')
  1447.           $.setStyle(el, ['display', 'none']);
  1448.         resolve();
  1449.       }
  1450.     });
  1451.   }
  1452.  
  1453.   /** @param {KeyboardEvent} e */
  1454.   static consumeEsc(e) {
  1455.     if (e.key === 'Escape')
  1456.       e.preventDefault();
  1457.   }
  1458.  
  1459.   static error(...args) {
  1460.     console.error(GM_info.script.name, ...args);
  1461.     console.trace();
  1462.   }
  1463. }
  1464.  
  1465.  
  1466. class Styles {
  1467.  
  1468.   static init() {
  1469.  
  1470.     Styles.REUSABLE = `${ID}-reusable`;
  1471.  
  1472.     const KBD_COLOR = '#0008';
  1473.  
  1474.     // language=HTML
  1475.     const SVG_ARROW = btoa(`
  1476.       <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16">
  1477.         <path stroke="${KBD_COLOR}" stroke-width="3" fill="none"
  1478.               d="M2.5,8.5H15 M9,2L2.5,8.5L9,15"/>
  1479.       </svg>`
  1480.       .replace(/>\s+</g, '><')
  1481.       .replace(/[\r\n]/g, ' ')
  1482.       .replace(/\s\s+/g, ' ')
  1483.       .trim()
  1484.     );
  1485.  
  1486.     const IMPORTANT = '!important;';
  1487.  
  1488.     // add keyRGB: r,g,b for use in rgba(), calculated from key:#rgb
  1489.     (function initColors(obj) {
  1490.       for (const [k, v] of Object.entries(obj)) {
  1491.         if (k.endsWith('RGB') || !v)
  1492.           continue;
  1493.         switch (typeof v) {
  1494.           case 'string': {
  1495.             const hexRRGGBB = v.length === 4 ? v.replace(/\w/g, '$&$&') : v;
  1496.             obj[k + 'RGB'] = parseInt(hexRRGGBB.substr(1, 2), 16) + ',' +
  1497.                              parseInt(hexRRGGBB.substr(3, 2), 16) + ',' +
  1498.                              parseInt(hexRRGGBB.substr(5, 2), 16);
  1499.             break;
  1500.           }
  1501.           case 'object':
  1502.             initColors(v);
  1503.             break;
  1504.         }
  1505.       }
  1506.     })(COLORS);
  1507.  
  1508.     // language=CSS
  1509.     pv.stylesOverride = [
  1510.       `
  1511.       :host {
  1512.         all: initial;
  1513.         border-color: transparent;
  1514.         display: none;
  1515.         opacity: 0;
  1516.         height: 33%;
  1517.         transition: opacity .25s cubic-bezier(.88,.02,.92,.66),
  1518.                     border-color .25s ease-in-out;
  1519.       }
  1520.       `,
  1521.  
  1522.       `
  1523.       :host {
  1524.         box-sizing: content-box;
  1525.         width: ${WIDTH}px;
  1526.         min-height: ${MIN_HEIGHT}px;
  1527.         position: fixed;
  1528.         right: 0;
  1529.         bottom: 0;
  1530.         padding: 0;
  1531.         margin: 0;
  1532.         background: white;
  1533.         box-shadow: 0 0 100px rgba(0,0,0,0.5);
  1534.         z-index: 999999;
  1535.         border-width: ${TOP_BORDER}px ${BORDER}px ${BORDER}px;
  1536.         border-style: solid;
  1537.       }
  1538.       :host(:not([style*="opacity: 1"])) {
  1539.         pointer-events: none;
  1540.       }
  1541.       :host([${ID}-type$="question"].${ID}-hasAnswerShelf) {
  1542.         border-image: linear-gradient(
  1543.           ${COLORS.question.back} 66%,
  1544.           ${COLORS.answer.back}) 1 1;
  1545.       }
  1546.       `.replace(/;/g, IMPORTANT),
  1547.  
  1548.       ...Object.entries(COLORS).map(([type, colors]) => `
  1549.         :host([${ID}-type$="${type}"]) {
  1550.           border-color: ${colors.back} !important;
  1551.         }
  1552.       `),
  1553.  
  1554.       `
  1555.       #${ID}-body {
  1556.         min-width: unset!important;
  1557.         box-shadow: none!important;
  1558.         padding: 0!important;
  1559.         margin: 0!important;
  1560.         background: unset!important;;
  1561.         display: flex;
  1562.         flex-direction: column;
  1563.         height: 100%;
  1564.       }
  1565.  
  1566.       #${ID}-title {
  1567.         all: unset;
  1568.         display: block;
  1569.         padding: 12px ${PADDING}px;
  1570.         font-weight: bold;
  1571.         font-size: 18px;
  1572.         line-height: 1.2;
  1573.         cursor: pointer;
  1574.       }
  1575.       #${ID}-title:hover {
  1576.         text-decoration: underline;
  1577.         text-decoration-skip: ink;
  1578.       }
  1579.       #${ID}-title:hover + #${ID}-meta {
  1580.         opacity: 1.0;
  1581.       }
  1582.  
  1583.       #${ID}-meta {
  1584.         position: absolute;
  1585.         font: bold 14px/${TOP_BORDER}px sans-serif;
  1586.         height: ${TOP_BORDER}px;
  1587.         top: -${TOP_BORDER}px;
  1588.         left: -${BORDER}px;
  1589.         right: ${BORDER * 2}px;
  1590.         padding: 0 0 0 ${BORDER + PADDING}px;
  1591.         display: flex;
  1592.         align-items: center;
  1593.         cursor: s-resize;
  1594.       }
  1595.       #${ID}-meta b {
  1596.         height: ${TOP_BORDER}px;
  1597.         display: inline-block;
  1598.         padding: 0 6px;
  1599.         margin-left: -6px;
  1600.         margin-right: 3px;
  1601.       }
  1602.  
  1603.       #${ID}-close {
  1604.         position: absolute;
  1605.         top: -${TOP_BORDER}px;
  1606.         right: -${BORDER}px;
  1607.         width: ${BORDER * 3}px;
  1608.         flex: none;
  1609.         cursor: pointer;
  1610.         padding: .5ex 1ex;
  1611.         font: normal 15px/1.0 sans-serif;
  1612.         color: #fff8;
  1613.       }
  1614.       #${ID}-close:after {
  1615.         content: "x";
  1616.       }
  1617.       #${ID}-close:active {
  1618.         background-color: rgba(0,0,0,.2);
  1619.       }
  1620.       #${ID}-close:hover {
  1621.         background-color: rgba(0,0,0,.1);
  1622.       }
  1623.  
  1624.       #${ID}-parts {
  1625.         position: relative;
  1626.         overflow-y: overlay; /* will replace with scrollbar-gutter once it's implemented */
  1627.         overflow-x: hidden;
  1628.         flex-grow: 2;
  1629.         outline: none;
  1630.       }
  1631.       [${ID}-type^="question"] #${ID}-parts {
  1632.         padding: ${(WIDTH - QUESTION_WIDTH) / 2}px !important;
  1633.       }
  1634.       [${ID}-type^="answer"] #${ID}-parts {
  1635.         padding: ${(WIDTH - ANSWER_WIDTH) / 2}px !important;
  1636.       }
  1637.       #${ID}-parts > .question-status {
  1638.         margin: -${PADDING}px -${PADDING}px ${PADDING}px;
  1639.         padding-left: ${PADDING}px;
  1640.       }
  1641.       #${ID}-parts .question-originals-of-duplicate {
  1642.         margin: -${PADDING}px -${PADDING}px ${PADDING}px;
  1643.         padding: ${PADDING / 2 >> 0}px ${PADDING}px;
  1644.       }
  1645.       #${ID}-parts > .question-status h2 {
  1646.         font-weight: normal;
  1647.       }
  1648.       #${ID}-parts a.SEpreviewable {
  1649.         text-decoration: underline !important;
  1650.         text-decoration-skip: ink;
  1651.       }
  1652.  
  1653.       #${ID}-parts .comment-actions {
  1654.         width: 20px !important;
  1655.       }
  1656.       #${ID}-parts .comment-edit,
  1657.       #${ID}-parts .delete-tag,
  1658.       #${ID}-parts .comment-actions > :not(.comment-score) {
  1659.         display: none;
  1660.       }
  1661.       #${ID}-parts .comments {
  1662.         border-top: none;
  1663.       }
  1664.       #${ID}-parts .comments .comment:last-child .comment-text {
  1665.         border-bottom: none;
  1666.       }
  1667.       #${ID}-parts .comments .new-comment-highlight .comment-text {
  1668.         -webkit-animation: highlight 9s cubic-bezier(0,.8,.37,.88);
  1669.         -moz-animation: highlight 9s cubic-bezier(0,.8,.37,.88);
  1670.         animation: highlight 9s cubic-bezier(0,.8,.37,.88);
  1671.       }
  1672.       #${ID}-parts .post-menu > span {
  1673.         opacity: .35;
  1674.       }
  1675.  
  1676.       #${ID}-parts #user-menu {
  1677.         position: absolute;
  1678.       }
  1679.       .${ID}-userCard {
  1680.         position: absolute;
  1681.         display: none;
  1682.         transition: opacity .25s cubic-bezier(.88,.02,.92,.66) .5s;
  1683.         margin-top: -3rem;
  1684.       }
  1685.       #${ID}-parts .wmd-preview a:not(.post-tag),
  1686.       #${ID}-parts .post-text a:not(.post-tag),
  1687.       #${ID}-parts .comment-copy a:not(.post-tag) {
  1688.         border-bottom: none;
  1689.       }
  1690.  
  1691.       #${ID}-answers-title {
  1692.         margin: .5ex 1ex 0 0;
  1693.         font-size: 18px;
  1694.         line-height: 1.0;
  1695.         float: left;
  1696.       }
  1697.       #${ID}-answers-title p {
  1698.         font-size: 11px;
  1699.         font-weight: normal;
  1700.         max-width: 8em;
  1701.         line-height: 1.0;
  1702.         margin: 1ex 0 0 0;
  1703.         padding: 0;
  1704.       }
  1705.       #${ID}-answers-title b,
  1706.       #${ID}-answers-title label {
  1707.         background: linear-gradient(#fff8 30%, #fff);
  1708.         width: 10px;
  1709.         height: 10px;
  1710.         padding: 2px;
  1711.         margin-right: 2px;
  1712.         box-shadow: 0 1px 3px #0008;
  1713.         border-radius: 3px;
  1714.         font-weight: normal;
  1715.         display: inline-block;
  1716.         vertical-align: middle;
  1717.       }
  1718.       #${ID}-answers-title b::after {
  1719.         content: "";
  1720.         display: block;
  1721.         width: 100%;
  1722.         height: 100%;
  1723.         background: url('data:image/svg+xml;base64,${SVG_ARROW}') no-repeat center;
  1724.       }
  1725.       #${ID}-answers-title b[mirrored]::after {
  1726.         transform: scaleX(-1);
  1727.       }
  1728.       #${ID}-answers-title label {
  1729.         width: auto;
  1730.         color: ${KBD_COLOR};
  1731.       }
  1732.  
  1733.       #${ID}-answers {
  1734.         all: unset;
  1735.         display: block;
  1736.         padding: 10px 10px 10px ${PADDING}px;
  1737.         font-weight: bold;
  1738.         line-height: 1.0;
  1739.         border-top: 4px solid rgba(${COLORS.answer.backRGB}, .37);
  1740.         background-color: rgba(${COLORS.answer.backRGB}, .37);
  1741.         color: ${COLORS.answer.fore};
  1742.         word-break: break-word;
  1743.       }
  1744.       #${ID}-answers a {
  1745.         color: ${COLORS.answer.fore};
  1746.         text-decoration: none;
  1747.         font-size: 11px;
  1748.         font-family: monospace;
  1749.         width: 32px;
  1750.         display: inline-block;
  1751.         position: relative;
  1752.         vertical-align: top;
  1753.         margin: 0 1ex 1ex 0;
  1754.         padding: 0 0 1.1ex 0;
  1755.       }
  1756.       [${ID}-type*="deleted"] #${ID}-answers a {
  1757.         color: ${COLORS.deleted.fore};
  1758.       }
  1759.       #${ID}-answers img {
  1760.         width: 32px;
  1761.         height: 32px;
  1762.       }
  1763.       #${ID}-answers a.deleted-answer {
  1764.         color: ${COLORS.deleted.fore};
  1765.         background: transparent;
  1766.         opacity: 0.25;
  1767.       }
  1768.       #${ID}-answers a.deleted-answer:hover {
  1769.         opacity: 1.0;
  1770.       }
  1771.       #${ID}-answers a:hover:not(.SEpreviewed) {
  1772.         text-decoration: underline;
  1773.         text-decoration-skip: ink;
  1774.       }
  1775.       #${ID}-answers a.SEpreviewed {
  1776.         background-color: ${COLORS.answer.fore};
  1777.         color: ${COLORS.answer.foreInv};
  1778.         outline: 4px solid ${COLORS.answer.fore};
  1779.       }
  1780.       #${ID}-answers a::after {
  1781.         white-space: nowrap;
  1782.         overflow: hidden;
  1783.         text-overflow: ellipsis;
  1784.         max-width: 40px;
  1785.         position: absolute;
  1786.         content: attr(title);
  1787.         top: 44px;
  1788.         left: 0;
  1789.         font: normal .75rem/1.0 sans-serif;
  1790.         opacity: .7;
  1791.       }
  1792.       #${ID}-answers a:only-child::after {
  1793.         max-width: calc(${WIDTH}px - 10em);
  1794.       }
  1795.       #${ID}-answers a:hover::after {
  1796.         opacity: 1;
  1797.       }
  1798.       .${ID}-accepted::before {
  1799.         content: "✔";
  1800.         position: absolute;
  1801.         display: block;
  1802.         top: 1.3ex;
  1803.         right: -0.7ex;
  1804.         font-size: 32px;
  1805.         color: #4bff2c;
  1806.         text-shadow: 1px 2px 2px rgba(0,0,0,0.5);
  1807.       }
  1808.  
  1809.       @-webkit-keyframes highlight {
  1810.         from {background: #ffcf78}
  1811.         to   {background: none}
  1812.       }
  1813.       `,
  1814.  
  1815.       ...Object.keys(COLORS).map(s => `
  1816.         #${ID}-title {
  1817.           background-color: rgba(${COLORS[s].backRGB}, 0.37);
  1818.           color: ${COLORS[s].fore};
  1819.         }
  1820.         #${ID}-meta {
  1821.           color: ${COLORS[s].fore};
  1822.         }
  1823.         #${ID}-meta b {
  1824.           color: ${COLORS[s].foreInv};
  1825.           background: ${COLORS[s].fore};
  1826.         }
  1827.         #${ID}-close {
  1828.           color: ${COLORS[s].fore};
  1829.         }
  1830.         #${ID}-parts::-webkit-scrollbar {
  1831.           background-color: rgba(${COLORS[s].backRGB}, 0.1);
  1832.         }
  1833.         #${ID}-parts::-webkit-scrollbar-thumb {
  1834.           background-color: rgba(${COLORS[s].backRGB}, 0.2);
  1835.         }
  1836.         #${ID}-parts::-webkit-scrollbar-thumb:hover {
  1837.           background-color: rgba(${COLORS[s].backRGB}, 0.3);
  1838.         }
  1839.         #${ID}-parts::-webkit-scrollbar-thumb:active {
  1840.           background-color: rgba(${COLORS[s].backRGB}, 0.75);
  1841.         }
  1842.       `
  1843.       // language=JS
  1844.         .replace(/#\w+-/g, `[${ID}-type$="${s}"] $&`)
  1845.       ),
  1846.  
  1847.       ...['deleted', 'closed'].map(s =>
  1848.       // language=CSS
  1849.       `
  1850.         #${ID}-answers {
  1851.           border-top-color: rgba(${COLORS[s].backRGB}, 0.37);
  1852.           background-color: rgba(${COLORS[s].backRGB}, 0.37);
  1853.           color: ${COLORS[s].fore};
  1854.         }
  1855.         #${ID}-answers a.SEpreviewed {
  1856.           background-color: ${COLORS[s].fore};
  1857.           color: ${COLORS[s].foreInv};
  1858.         }
  1859.         #${ID}-answers a.SEpreviewed:after {
  1860.           border-color: ${COLORS[s].fore};
  1861.         }
  1862.       `
  1863.       // language=JS
  1864.         .replace(/#\w+-/g, `[${ID}-type$="${s}"] $&`)
  1865.       ),
  1866.     ].join('\n');
  1867.  
  1868.     Styles.init = true;
  1869.   }
  1870. }
  1871.  
  1872. function $(selector, node = pv.shadow) {
  1873.   return node && node.querySelector(selector);
  1874. }
  1875.  
  1876. Object.assign($, {
  1877.  
  1878.   all(selector, node = pv.shadow) {
  1879.     return node ? [...node.querySelectorAll(selector)] : [];
  1880.   },
  1881.  
  1882.   on(eventName, node, fn, options) {
  1883.     return node.addEventListener(eventName, fn, options);
  1884.   },
  1885.  
  1886.   off(eventName, node, fn, options) {
  1887.     return node.removeEventListener(eventName, fn, options);
  1888.   },
  1889.  
  1890.   remove(selector, node = pv.shadow) {
  1891.     // using the much faster querySelector since there's just a few elements
  1892.     for (let el; (el = node.querySelector(selector));)
  1893.       el.remove();
  1894.   },
  1895.  
  1896.   text(selector, node = pv.shadow) {
  1897.     const el = typeof selector === 'string' ?
  1898.       node && node.querySelector(selector) :
  1899.       selector;
  1900.     return el ? el.textContent.trim() : '';
  1901.   },
  1902.  
  1903.   create(
  1904.     selector,
  1905.     opts = {},
  1906.     children = opts.children ||
  1907.                (typeof opts !== 'object' || Util.isIterable(opts)) && opts
  1908.   ) {
  1909.     const EOL = selector.length;
  1910.     const idStart = (selector.indexOf('#') + 1 || EOL + 1) - 1;
  1911.     const clsStart = (selector.indexOf('.', idStart < EOL ? idStart : 0) + 1 || EOL + 1) - 1;
  1912.     const tagEnd = Math.min(idStart, clsStart);
  1913.     const tag = (tagEnd < EOL ? selector.slice(0, tagEnd) : selector) || opts.tag || 'div';
  1914.     const id = idStart < EOL && selector.slice(idStart + 1, clsStart) || opts.id || '';
  1915.     const cls = clsStart < EOL && selector.slice(clsStart + 1).replace(/\./g, ' ') ||
  1916.                 opts.className ||
  1917.                 '';
  1918.     const el = id && pv.shadow && pv.shadow.getElementById(id) ||
  1919.                document.createElement(tag);
  1920.     if (el.id !== id)
  1921.       el.id = id;
  1922.     if (el.className !== cls)
  1923.       el.className = cls;
  1924.     const hasOwnProperty = Object.hasOwnProperty;
  1925.     for (const key in opts) {
  1926.       if (!hasOwnProperty.call(opts, key))
  1927.         continue;
  1928.       const value = opts[key];
  1929.       switch (key) {
  1930.         case 'tag':
  1931.         case 'id':
  1932.         case 'className':
  1933.         case 'children':
  1934.           break;
  1935.         case 'dataset': {
  1936.           const dataset = el.dataset;
  1937.           for (const k in value) {
  1938.             if (hasOwnProperty.call(value, k)) {
  1939.               const v = value[k];
  1940.               if (dataset[k] !== v)
  1941.                 dataset[k] = v;
  1942.             }
  1943.           }
  1944.           break;
  1945.         }
  1946.         case 'attributes': {
  1947.           for (const k in value) {
  1948.             if (hasOwnProperty.call(value, k)) {
  1949.               const v = value[k];
  1950.               if (el.getAttribute(k) !== v)
  1951.                 el.setAttribute(k, v);
  1952.             }
  1953.           }
  1954.           break;
  1955.         }
  1956.         default:
  1957.           if (el[key] !== value)
  1958.             el[key] = value;
  1959.       }
  1960.     }
  1961.     if (children) {
  1962.       if (!hasOwnProperty.call(opts, 'textContent'))
  1963.         el.textContent = '';
  1964.       $.appendChildren(el, children);
  1965.     }
  1966.     let before, after, parent;
  1967.     if ((before = opts.before) && before !== el.nextSibling && before !== el)
  1968.       before.insertAdjacentElement('beforebegin', el);
  1969.     else if ((after = opts.after) && after !== el.previousSibling && after !== el)
  1970.       after.insertAdjacentElement('afterend', el);
  1971.     else if ((parent = opts.parent) && parent !== el.parentNode)
  1972.       parent.appendChild(el);
  1973.     return el;
  1974.   },
  1975.  
  1976.   appendChild(parent, child, shouldClone = true) {
  1977.     if (!child)
  1978.       return;
  1979.     if (child.nodeType)
  1980.       return parent.appendChild(shouldClone ? document.importNode(child, true) : child);
  1981.     if (Util.isIterable(child))
  1982.       return $.appendChildren(parent, child, shouldClone);
  1983.     else
  1984.       return parent.appendChild(document.createTextNode(child));
  1985.   },
  1986.  
  1987.   appendChildren(newParent, children) {
  1988.     if (!Util.isIterable(children))
  1989.       return $.appendChild(newParent, children);
  1990.     const fragment = document.createDocumentFragment();
  1991.     for (const el of children)
  1992.       $.appendChild(fragment, el);
  1993.     return newParent.appendChild(fragment);
  1994.   },
  1995.  
  1996.   setStyle(el, ...props) {
  1997.     const style = el.style;
  1998.     const s0 = style.cssText;
  1999.     let s = s0;
  2000.  
  2001.     for (const p of props) {
  2002.       if (!p)
  2003.         continue;
  2004.  
  2005.       const [name, value, important = true] = p;
  2006.       const rValue = value + (important && value ? ' !important' : '');
  2007.       const rx = new RegExp(`(^|[\\s;])${name}(\\s*:\\s*)([^;]*?)(\\s*(?:;|$))`, 'i');
  2008.       const m = rx.exec(s);
  2009.  
  2010.       if (!m && value) {
  2011.         const rule = name + ': ' + rValue;
  2012.         s += !s || s.endsWith(';') ? rule : '; ' + rule;
  2013.         continue;
  2014.       }
  2015.  
  2016.       if (!m && !value)
  2017.         continue;
  2018.  
  2019.       const [, sep1, sep2, oldValue, sep3] = m;
  2020.       if (value !== oldValue) {
  2021.         s = s.slice(0, m.index) +
  2022.             sep1 + (rValue ? name + sep2 + rValue + sep3 : '') +
  2023.             s.slice(m.index + m[0].length);
  2024.       }
  2025.     }
  2026.  
  2027.     if (s !== s0)
  2028.       style.cssText = s;
  2029.   },
  2030. });