fix: framework demos fail when system.js faces some auto re-exports (#28512)

Author: VasilyStrelyaev

apps/demos/utils/bundle/index.js

@@ -5,6 +5,7 @@ const Builder = require('systemjs-builder');
 const babel = require('@babel/core');
 const url = require('url');
 
+const GRID_COMMON_STAR_IMPORT = 'exports.Grids = __importStar(require("./grids"));';
 
 // https://stackoverflow.com/questions/42412965/how-to-load-named-exports-with-systemjs/47108328
 const prepareModulesToNamedImport = () => {
@@ -216,13 +217,22 @@ const prepareConfigs = (framework)=> {
             ]
           };
 
+          // This auto-generated runtime import is useless because grid.js exports only types,
+          // but System.js transpiles this import into code that crashes when triggered in a Demo.
+          const removeImportTranspiledToCrashingCode = (result) => {
+            if(result.code.includes(GRID_COMMON_STAR_IMPORT)) {
+              result.code = result.code.replace(GRID_COMMON_STAR_IMPORT, '');
+            }
+          }
+
           const result = new Promise((resolve) => {
             // systemjs-builder uses babel 6, so we use babel 7 here for transpiling ES2020
             babel.transformFile(url.fileURLToPath(load.name), babelOptions, (err, result) => {
                 if(err) {
                   fetch(load).then(r => resolve(r));
                   console.log('Unexpected transipling error (babel 7): ' + err);
                 } else {
+                  removeImportTranspiledToCrashingCode(result);
                   resolve(result.code);
                 }
             });