in progress

rollup.config.js

@@ -9,7 +9,7 @@ import nodePolyfills from 'rollup-plugin-node-polyfills';
 // eslint-disable-next-line no-console
 rimraf('./dist', () => console.info('recreating dist'));
 
-const config = {
+const config = [{
   input: 'src/editor/index.js',
   preserveEntrySignatures: false,
   output: [
@@ -20,6 +20,13 @@ const config = {
       sourcemap: true
       // dir: 'dist/editor'
     },
+    {
+      format: 'system',
+      file: 'dist/editor/index-system.js',
+      inlineDynamicImports: true,
+      sourcemap: true
+      // dir: 'dist/editor'
+    },
     {
       format: 'iife',
       file: 'dist/editor/index-iife.js',
@@ -45,6 +52,26 @@ const config = {
           transform: (contents) => contents.toString()
             .replace('<script type="module" src="index.js">', '<script defer="defer" src="index-iife.js">')
         },
+        {
+          src: 'src/editor/index.html',
+          dest: 'dist/editor',
+          rename: 'index-system.html',
+          transform: (contents) => contents.toString()
+            .replace('<script type="module" src="index.js">',
+              `<script>
+              if (!window.supportsDynamicImport) {
+                const systemJsLoaderTag = document.createElement('script');
+                systemJsLoaderTag.src = './s.min.js';
+                systemJsLoaderTag.addEventListener('load', function () {
+                  System.import('./index-system.js');
+                });
+                document.head.appendChild(systemJsLoaderTag);
+              }`)
+        },
+        {
+          src: ['node_modules/systemjs/dist/s.min.js', 'node_modules/systemjs/dist/s.min.js.map'],
+          dest: 'dist/editor'
+        },
         {
           src: 'src/editor/index.html',
           dest: 'dist/editor',
@@ -69,14 +96,14 @@ const config = {
         {src: 'src/editor/svgedit.css', dest: 'dist/editor'}
       ]
     }),
-    commonjs(),
-    babel({babelHelpers: 'bundled'}),
-    nodePolyfills(),
     nodeResolve({
       browser: true,
       preferBuiltins: true
-    })
+    }),
+    commonjs(),
+    babel({babelHelpers: 'bundled'}),
+    nodePolyfills()
   ]
-};
+}];
 
 export default config;