IE 11 Support via WebPack Config

samples/react-calendar-feed/gulpfile.js

@@ -4,4 +4,51 @@ const gulp = require('gulp');
 const build = require('@microsoft/sp-build-web');
 build.addSuppression(`Warning - [sass] The local CSS class 'ms-Grid' is not camelCase and will not be type-safe.`);
 
+
+build.configureWebpack.mergeConfig({
+  additionalConfiguration: (generatedConfiguration) => {
+    generatedConfiguration.module.rules.push({
+      test: /\.js$/,
+     exclude: /node_modules\/(?!(rss-paser|@babel))/,
+      use: {
+        loader: 'babel-loader',
+        options: {
+          presets: [
+            ["@babel/preset-env",
+              {
+                targets: {
+                  "ie": "11"
+                }
+              }
+            ]
+          ]
+        }
+      }
+    });
+
+    return generatedConfiguration;
+  }
+});
+
+/* 
+Show current Webpack configuration
+*/
+/*
+build.configureWebpack.mergeConfig({
+  additionalConfiguration: (generatedConfig) => {
+    console.log('<webpack.config type="object">');
+    console.log(generatedConfig);
+    console.log('</webpack.config>');
+
+    console.log('<webpack.config type="string">');
+    console.log(JSON.stringify(generatedConfig));
+    console.log('</webpack.config>');
+
+    return generatedConfig;
+  }
+});
+*/
+
+
+
 build.initialize(gulp);

samples/react-calendar-feed/package.json

@@ -42,6 +42,8 @@
     "@types/react": "16.8.8"
   },
   "devDependencies": {
+    "@babel/core": "^7.10.4",
+    "@babel/preset-env": "^7.10.4",
     "@microsoft/rush-stack-compiler-2.9": "0.7.16",
     "@microsoft/rush-stack-compiler-3.3": "0.3.5",
     "@microsoft/sp-build-web": "1.10.0",
@@ -51,6 +53,8 @@
     "@types/chai": "3.4.34",
     "@types/mocha": "2.2.38",
     "ajv": "~5.2.2",
-    "gulp": "~3.9.1"
+    "babel-loader": "^8.1.0",
+    "gulp": "~3.9.1",
+    "webpack": "^4.43.0"
   }
 }