export const loadScript = (src) =>
  new Promise((resolve, reject) => {
    const existing = document.querySelector(`script[src="${src}"]`);

    if (existing) {
      if (existing.dataset.loaded === "true") {
        resolve();
        return;
      }

      existing.addEventListener("load", () => resolve(), { once: true });
      existing.addEventListener("error", () => reject(new Error(`Failed to load ${src}`)), {
        once: true
      });
      return;
    }

    const script = document.createElement("script");
    script.src = src;
    script.async = true;
    script.addEventListener(
      "load",
      () => {
        script.dataset.loaded = "true";
        resolve();
      },
      { once: true }
    );
    script.addEventListener("error", () => reject(new Error(`Failed to load ${src}`)), {
      once: true
    });
    document.head.appendChild(script);
  });