Mastodon Markdown

mastodon-markdown.user.js

// ==UserScript==
// @name Markdown
// @namespace Paars
// @author Kura
// @version 1.1.1
// @match *://niu.moe/web/*
// @require https://cdn.rawgit.com/chjj/marked/8f9d0b72/marked.min.js
// @run-at document-end
// @grant GM_addStyle
// ==/UserScript==

marked.setOptions({ breaks: false })

GM_addStyle(`
i, em { font-style: italic; }
b, strong{ font-weight: bold; }
u { text-decoration: underline; }
.status > div:nth-child(2) { white-space: inherit; }
`)

function attributesToString(attr) {
  return Array.from(attr).map(a => `${a.name}="${a.value}"`).join(" ")
}

function nodeToString(n) {
  let data = ""
  for (let idx = 0; idx < n.childNodes.length; idx++) {
    const c = n.childNodes[idx]
    if (c.nodeType === Node.TEXT_NODE) {
      data += c.nodeValue
      continue
    }
    
    switch (c.nodeName) {
      case "IMG":
      case "BR":
        data += "<" + c.nodeName.toLowerCase() + " " + attributesToString(c.attributes) + " />"
        continue
      case "P": 
        break
      default:
        data += "<" + c.nodeName.toLowerCase() + " " + attributesToString(c.attributes) + ">"
    }
    
    data += nodeToString(c)
    
    switch (c.nodeName) {
      case "P":
        data += "\n\n";
        break
      default:
        data += "</" + c.nodeName.toLowerCase() + ">"; 
        break
    }
  }
  return data
}

const observer = new MutationObserver(records => {
  records.forEach(r => {
    if (!r.addedNodes.length) {
      return
    }
    
    r.addedNodes.forEach(n => {
      if (n.nodeName !== "ARTICLE" && !(n.classList && n.classList.contains("detailed-status__wrapper"))) {
        return
      }
      
      const status = n.querySelector(".status > div:nth-child(2), .detailed-status > div:nth-child(2)")
      if (!status) {
        return
      }
      const txt = nodeToString(status)
      const md = marked(txt)
      const frag = document.createRange().createContextualFragment(md)
      while (status.firstChild) status.removeChild(status.firstChild)
      status.appendChild(frag)
    })
  })
})

Array.from(document.querySelectorAll("#mastodon")).forEach(list => observer.observe(list, {
  childList: true,
  attributes: false,
  characterData: false,
  subtree: true
}))

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