Added homepage polyfills. (codesandbox#786)

Author: lbogdan

packages/common/detect-old-browser.js

@@ -0,0 +1,27 @@
+function detectIE() {
+  const ua = window.navigator.userAgent;
+
+  const msie = ua.indexOf('MSIE ');
+  if (msie > 0) {
+    // IE 10 or older => return version number
+    return parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
+  }
+
+  const trident = ua.indexOf('Trident/');
+  if (trident > 0) {
+    // IE 11 => return version number
+    const rv = ua.indexOf('rv:');
+    return parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
+  }
+
+  // other browser
+  return false;
+}
+
+function detectOpera() {
+  return navigator.userAgent.indexOf('Opera') > -1;
+}
+
+export default function detectOldBrowser() {
+  return detectIE() || detectOpera();
+}

packages/common/load-dynamic-polyfills.js

@@ -1,29 +1,7 @@
-function detectIE() {
-  const ua = window.navigator.userAgent;
-
-  const msie = ua.indexOf('MSIE ');
-  if (msie > 0) {
-    // IE 10 or older => return version number
-    return parseInt(ua.substring(msie + 5, ua.indexOf('.', msie)), 10);
-  }
-
-  const trident = ua.indexOf('Trident/');
-  if (trident > 0) {
-    // IE 11 => return version number
-    const rv = ua.indexOf('rv:');
-    return parseInt(ua.substring(rv + 3, ua.indexOf('.', rv)), 10);
-  }
-
-  // other browser
-  return false;
-}
-
-function detectOpera() {
-  return navigator.userAgent.indexOf('Opera') > -1;
-}
+import detectOldBrowser from 'common/detect-old-browser';
 
 export default function requirePolyfills() {
-  if (detectIE() || detectOpera()) {
+  if (detectOldBrowser()) {
     return import(/* webpackChunkName: 'polyfills' */ 'babel-polyfill');
   }
 

packages/homepage/gatsby-browser.js

@@ -1,2 +1,7 @@
-import 'core-js/es6/map';
-import 'core-js/es6/set';
+import detectOldBrowser from 'common/detect-old-browser';
+
+exports.onClientEntry = () => {
+  if (detectOldBrowser()) {
+    require('babel-polyfill');
+  }
+};