AsyncInjector.js

class AsyncInjector {
 constructor() {}

 injectScript(
   document: any,
   src: string,
   async: boolean = false,
   callbackLoaded = () => {}
 ) {
   let script = document.createElement("script");
   let id = src.slice(src.lastIndexOf("/") + 1);
   script.type = "text/javascript";
   script.async = async;
   script.onload = callbackLoaded;
   script.src = src;
   script.id = id;

   if (!document.getElementById(id)){
     document.getElementsByTagName("head")[0].appendChild(script);
   }
 }
}

AsyncInjector.min.js

class AsyncInjector{constructor(){}injectScript(e,t,c,a=(()=>{})){let n=e.createElement("script"),s=t.slice(t.lastIndexOf("/")+1);n.type="text/javascript",n.async=c,n.onload=a,n.src=t,n.id=s,e.getElementById(s)||e.getElementsByTagName("head")[0].appendChild(n)}}