userscript-utils.js

const ensureDomLoaded = (f) => {
  if (["interactive", "complete"].indexOf(document.readyState) > -1) {
    f();
  } else {
    let triggered = false;
    document.addEventListener("DOMContentLoaded", () => {
      if (!triggered) {
        triggered = true;
        setTimeout(f, 1);
      }
    });
  }
};
const awaitElement = (q, f) =>
  ensureDomLoaded(() => {
    let t = setInterval(() => {
      let e = document.querySelector(q);
      if (e) {
        f(e);
        clearInterval(t);
      }
    }, 10);
    setInterval(() => clearInterval(t), 30000);
  });