function for include script

scriptInclude.js

export function script(url) {
  if (Array.isArray(url)) {
    let self = this;
    let prom = [];
    url.forEach(function (item) {
      prom.push(self.script(item));
    });

    return Promise.all(prom);
  }

  return new Promise(function (resolve, reject) {
    let r = false;
    let t = document.getElementsByTagName("script")[0];
    let s = document.createElement("script");

    s.type = "text/javascript";
    s.src = url;
    s.async = true;
    s.onload = s.onreadystatechange = function () {
      if (!r && (!this.readyState || this.readyState === "complete")) {
        r = true;
        resolve(this);
      }
    };
    s.onerror = s.onabort = reject;
    t.parentNode.insertBefore(s, t);
  });
}