Userscript to sort Pittsburgh Regional Transit bus schedules numerically

sort-prt-bus-schedules.user.js

// ==UserScript==
// @name     Sort Pittsburgh Regional Transit bus schedules numerically
// @version  2
// @include  https://www.rideprt.org/all-schedules/
// @grant    none
// ==/UserScript==

// This script is dedicated to the public domain under Creative Commons CC0 1.0 Universal
// <https://creativecommons.org/publicdomain/zero/1.0/>

(function (document, window) {
  var busNumberRegex = /^([A-Z]?)([0-9]+)([A-Z]?)$/;

  function compareBusNumbers(a, b) {
    var aParsed = busNumberRegex.exec(a);
    var bParsed = busNumberRegex.exec(b);

    if (aParsed === null || bParsed === null) {
      // If parsing fails, fall back to string comparison
      return (a > b) - (a < b);
    }

    var aPrefix = aParsed[1];
    var aNumber = Number(aParsed[2]);
    var aSuffix = aParsed[3];
    var bPrefix = bParsed[1];
    var bNumber = Number(bParsed[2]);
    var bSuffix = bParsed[3];

    if (aPrefix !== bPrefix) {
      return (aPrefix > bPrefix) - (aPrefix < bPrefix);
    }
    if (aNumber !== bNumber) {
      return (aNumber > bNumber) - (aNumber < bNumber);
    }
    if (aSuffix !== bSuffix) {
      return (aSuffix > bSuffix) - (aSuffix < bSuffix);
    }
    return 0;
  }

  function getBusNumber(linkElement) {
    return linkElement.textContent.split(' ')[0];
  }

  var waitForLoad = window.setInterval(function () {
    var scheduleCells = document.getElementById('showData1').getElementsByTagName('td');
    var scheduleLinks = [];

    for (var i = 0; i < scheduleCells.length; i++) {
      var cellLinks = scheduleCells[i].getElementsByTagName('a');
      if (cellLinks.length > 0) {
        scheduleLinks.push(scheduleCells[i].removeChild(cellLinks[0]));
      }
    }

    if (scheduleLinks.length === 0) {
      return;
    }

    scheduleLinks.sort(function (a, b) { return compareBusNumbers(getBusNumber(a), getBusNumber(b)); });

    for (var i = 0; i < scheduleLinks.length; i++) {
      scheduleCells[i].appendChild(scheduleLinks[i]);
    }

    window.clearInterval(waitForLoad);
  }, 500);
})(document, window);