booru-image-view-file-names.user.js

// ==UserScript==
// @name        booru-image-view-file-names
// @namespace   Violentmonkey Scripts
// @match       https://derpibooru.org/*
// @match       https://trixiebooru.org/*
// @grant       none
// @version     1.0
// @author      mdashlw
// @description 4/10/2024, 1:47:21 PM
// @run-at      document-start
// ==/UserScript==

function runAfterDom(fn) {
  if (document.readyState === "loading") {
    document.addEventListener("readystatechange", fn, { once: true });
  } else {
    fn();
  }
}

if (window.location.pathname.startsWith("/images/")) {
  const imageId = window.location.pathname.split("/")[2];

  if (!isNaN(imageId)) {
    fetch(`/api/v1/json/images/${imageId}`)
      .then((response) => response.json())
      .then(({ image }) => {
        if (image.hidden_from_users || !image.name) {
          return;
        }

        runAfterDom(() => {
          const extrameta = document.querySelector("#extrameta");

          if (!extrameta) {
            return;
          }

          const filenameEl = document.createElement("span");
          filenameEl.style.paddingLeft = "12px";
          filenameEl.textContent = image.name;

          extrameta.appendChild(filenameEl);
        });
      });
  }
}