index.ts

/// <reference types="@globalpayments/js" />
import version  from "@globalpayments/js/src/lib/version";

/**
 * Prevent multiple copies of the Global Payments JavaScript
 * library from being loaded by only using a single Promise.
 */
let libraryLoaded: Promise<typeof window.GlobalPayments>;

/**
 * Loads the Global Payments JavaScript library asynchronously, using a
 * resolved `Promise` to signal that the library has loaded.
 *
 * @param url
 *
 * @returns The resolved library
 */
export function loadLibrary(
  url?: string
): Promise<typeof window.GlobalPayments> {
  if (libraryLoaded) {
    return libraryLoaded;
  }

  if (window.GlobalPayments) {
    return (libraryLoaded = Promise.resolve(window.GlobalPayments));
  }

  if (!url) {
    url = `https://js.globalpay.com/${version}/globalpayments.js`;
  }

  return (libraryLoaded = new Promise((resolve) => {
    try {
      const script = document.createElement("script");
      script.defer = true;
      script.src = url || "";
      script.onload = () => {
        resolve(window.GlobalPayments);
      };
      document.body.appendChild(script);
    } catch (e) {
      /** */
    }
  }));
}