Fix loading of external resources after dependencies

Author: Ives van Hoorne

src/sandbox/external-resources.js

@@ -27,6 +27,7 @@ function addCSS(resource: string) {
 function addJS(resource: string) {
   const script = document.createElement('script');
   script.setAttribute('src', resource);
+  script.setAttribute('async', false);
   script.setAttribute('id', 'external-js');
   document.head.appendChild(script);
 }

src/sandbox/index.js

@@ -60,12 +60,12 @@ async function compile(message) {
   if (url == null || url !== newUrl) {
     fetching = true;
     url = newUrl;
+    handleExternalResources(externalResources);
     await addDependencyBundle();
     fetching = false;
     window.parent.postMessage('Ready!', host);
     return;
   }
-  handleExternalResources(externalResources);
 
   try {
     const html = getIndexHtml(modules);