A userscript to replace the incorrect "follow" language on inoreader with "subscribe"

inoreader_subscribe.js

// ==UserScript==
// @name       inoreader: we subscribe to RSS feeds; we do not follow them
// @namespace  inoreader_subscribe
// @include    https://www.inoreader.com/*
// @version    1
// ==/UserScript==

// Based on https://dev.to/kevin940726/one-fun-trick-to-observe-elements-in-realtime-without-mutationobserver-22kj

function queryElements(selector, callback) {
  const elements = document.querySelectorAll(selector);
  elements.forEach(element => callback(element));
}

function observe(selectors, callback) {
  for (let selector of selectors) {
    // Call it once for elements present before MutationObserver
    queryElements(selector, callback);
  }

  const observer = new MutationObserver(() => {
    for (let selector of selectors) {
      queryElements(selector, callback);
    }
  });

  observer.observe(document.documentElement, {
    //attributes: true,
    childList: true,
    //characterData: true,
    subtree: true,
  });
}

const selectors = [
  // Blue "Follow" buttons
  'button.bluebutton[onclick*="add_subscription("]',
  // "Unfollow" in the menu for a feed
  // "Unfollow all" in the menu for a feed folder
  'div.inno_toolbar_button_menu_item',
  // Modal dialog after clicking Unsubscribe
  'div#xconfirm',
  // Modal dialog after clicking Feed Properties
  'button.redbutton',
  'div.feed_info_dialog_header_info_meta_row',
  'div.folder_dialog_line_header',
  // Temporary banner at the top of the viewport
  'div.bn_text',
  // "Track keyword mentions across your followed feeds or all public articles."
  // on https://www.inoreader.com/monitored_keywords via "Monitored keywords" in the sidebar
  'div.graylink',
  // https://www.inoreader.com/apps
  'div.apps_heading',
  'a.bookmark_link',
  // "Recommended sources", the right sidebar on https://www.inoreader.com/dashboard
  'span.discover_feed_kpi_item_first',
];

observe(selectors, element => {
  switch (element.tagName) {
    case "BUTTON":
      if (element.innerText == "Follow") {
        element.innerText = "Subscribe";
      } else if (element.innerText == "Unfollow") {
        element.innerText = "Unsubscribe";
      }
      break;
    case "DIV":
      const classList = element.classList;
      if (classList.contains("inno_toolbar_button_menu_item")) {
        if (element.innerText == "Unfollow") {
          element.innerText = "Unsubscribe";
        } else if (element.innerText == "Unfollow all") {
          element.innerText = "Unsubscribe from all";
        }
      } else if (classList.contains("bn_text") && element.firstChild?.textContent.startsWith("Followed ")) {
        element.firstChild.textContent = element.firstChild.textContent.replace("Followed ", "Subscribed to ");
      } else if (classList.contains("graylink") && element.firstChild?.textContent.includes(" followed ")) {
        element.firstChild.textContent = element.firstChild.textContent.replace(" followed ", " subscribed ");
      } else if (classList.contains("apps_heading") && element.firstChild?.textContent.includes("Follow ")) {
        element.firstChild.textContent = element.firstChild.textContent.replace("Follow ", "Subscribe ");
      } else if (classList.contains("feed_info_dialog_header_info_meta_row") && element.firstChild?.textContent.includes("Date followed: ")) {
        element.firstChild.textContent = element.firstChild.textContent.replace("Date followed: ", "Date subscribed: ");
      } else if (classList.contains("folder_dialog_line_header") && element.firstChild?.textContent.includes("Followers:")) {
        element.firstChild.textContent = element.firstChild.textContent.replace("Followers:", "Subscribers:");
      } else if (element.id == "xconfirm" && element.firstChild?.textContent == "Do you want to unfollow this feed?") {
        element.firstChild.textContent = "Do you want to unsubscribe from this feed?";
      }
      break;
    case "A":
      if (element.classList.contains("bookmark_link") && element.innerText == "Follow in Inoreader") {
        element.innerText = "Subscribe in Inoreader";
      }
      break;
    case "SPAN":
      if (element.classList.contains("discover_feed_kpi_item_first") && element.innerText.endsWith(" followers")) {
        element.innerText = element.innerText.replace(" followers", " subscribers");
      }
      break;
  }
});