Remove User ID from Stack Overflow Share URLs

Removes the User ID from the URL displayed by the "Share" button for questions and answers on Stack Overflow and related sites. For a description of why the User ID was added, see https://meta.stackoverflow.com/q/277769

/* eslint-disable max-len */
// ==UserScript==
// @name        Remove User ID from Stack Overflow Share URLs
// @namespace   https://kevinlocke.name/userscripts
// @description Removes the User ID from the URL displayed by the "Share" button for questions and answers on Stack Overflow and related sites.  For a description of why the User ID was added, see https://meta.stackoverflow.com/q/277769
// @match       https://*.askubuntu.com/*
// @match       https://*.mathoverflow.net/*
// @match       https://*.serverfault.com/*
// @match       https://*.stackapps.com/*
// @match       https://*.stackexchange.com/*
// @match       https://*.stackoverflow.com/*
// @match       https://*.superuser.com/*
// @version     1.0.1
// @license     MIT
// @grant       none
// @supportURL https://github.com/kevinoid/stackoverflow-share-remove-user-id
// ==/UserScript==
/* eslint-enable max-len */

// Note: Domain list from https://stackexchange.com/sites?view=list

'use strict';

// Amount of information to log to the console.  Lower = more.
const logLevel = 3;

// Simple logging framework
function notLogged() {}
const log = {
  /* eslint-disable no-console */
  error: logLevel < 5 ? console.error : notLogged,
  warn: logLevel < 4 ? console.warn : notLogged,
  info: logLevel < 3 ? console.info : notLogged,
  log: logLevel < 2 ? console.log : notLogged,
  debug: logLevel < 1 ? (console.debug || console.log) : notLogged
  /* eslint-enable no-console */
};

function forEach(arrayLike, callback, thisArg) {
  Array.prototype.forEach.call(arrayLike, callback, thisArg);
}

/** Removes the User ID from the URL displayed in response to clicking a
 * "Share" link.
 */
function removeUserIDOnClick(evt) {
  const {classList} = evt.target;
  if (!classList.contains('js-share-link')
      && !classList.contains('short-link')) {
    // click was not on "Share" link
    log.debug('Ignoring click not on .js-share-link or .short-link.');
    return;
  }

  const inputs = evt.target.parentNode.getElementsByTagName('input');
  if (inputs.length === 0) {
    log.warn('Could not find "Share" URL input element.');
    return;
  }

  forEach(inputs, (input) => {
    // Only change URLs with known formats to avoid breaking other URL formats
    const oldUrl = input.value;
    const newUrl
      = oldUrl.replace(/^(https?:\/\/[^/]*\/[aq]\/[0-9]+)\/[0-9]+$/, '$1');
    if (newUrl === oldUrl) {
      if (/^https?:\/\/[^/]*\/[aq]\/[0-9]+$/.test(oldUrl)) {
        log.debug(`Ignoring "Share" URL without User ID: ${oldUrl}`);
      } else {
        log.warn(`Ignoring unrecognized "Share" URL: ${oldUrl}`);
      }

      return;
    }

    log.debug(`Changed "Share" URL from ${oldUrl} to ${newUrl}`);
    input.value = newUrl;

    // Changing the value clears the selection.  Select the URL text.
    input.setSelectionRange(0, newUrl.length);
  });
}

// Wait until load event to register click event listener so that it is
// registered (and therefore runs) after the Stack Overflow click listener.
window.addEventListener(
  'load',
  () => document.addEventListener('click', removeUserIDOnClick, false),
  false
);