dynamically load a script

loadScript.js

const loadScript = (() => {
  const _loadedScripts = {};

  return (src) => {
    if (_loadedScripts[src]) {
      return _loadedScripts[src];
    }

    return ( // eslint-disable-line no-return-assign
      _loadedScripts[src] = new Promise(_injectScriptTag)
    );

    function _injectScriptTag(resolve, reject) {
      const element = document.createElement('script');
      const target = document.getElementsByTagName('script')[0];

      element.src = src;
      element.async = 1;
      element.onload = resolve;
      element.onerror = reject;

      target.parentNode.insertBefore(element, target);
    }
  };
})();


export default loadScript;