replace t.co with original links

twitter_remove_t_co.js

// ==UserScript==
// @name Twitter remove t.co
// @description replace t.co with original links
// @match https://twitter.com/*
// @version 0.1
// ==/UserScript==

const PRIMARY_COLUMN = '[data-testid="primaryColumn"]';
const SIDEBAR_COLUMN = '[data-testid="sidebarColumn"]';
const A_HREF_T_CO = 'a[href^="https://t.co"]';

// observe body and wait for primaryColumn
let mo = new MutationObserver((mutationList, observer) => {
  for (let i = 0; i < mutationList.length; i++) {
    const mutation = mutationList[i];
    for (let j = 0; j < mutation.addedNodes.length; j++) {
      const node = mutation.addedNodes[j];
      if (node.querySelector(PRIMARY_COLUMN)) {
        replace(node);
        init();
        observer.disconnect();
        mo = null;
      }
    }
  }
}).observe(document.body, { childList: true, subtree: true });

// replace all href inside the node
function replace(node) {
  const a = node.querySelectorAll(A_HREF_T_CO);
  for (let i = 0; i < a.length; i++) {
    const elm = a[i];
    const href = elm.textContent;
    if (href) {
      elm.setAttribute('href', href.endsWith('…') ? href.substr(0, href.length - 1) : href);
    }
  }
}

// observe primaryColumn and replace href
function init() {
  const target = document.querySelector('main');
  new MutationObserver((mutationList, observer) => {
    for (let i = 0; i < mutationList.length; i++) {
      const mutation = mutationList[i];
      for (let j = 0; j < mutation.addedNodes.length; j++) {
        const node = mutation.addedNodes[j];
        replace(node);
      }
    }
  }).observe(target, { childList: true, subtree: true });
}