Add support for IE 11 (#165)

ServerlessLibraryAPI/ClientApp/package.json

@@ -8,6 +8,7 @@
     "node-sass": "^4.11.0",
     "office-ui-fabric-react": "^6.168.0",
     "react": "^16.8.6",
+    "react-app-polyfill": "^1.0.0",
     "react-dom": "^16.8.6",
     "react-redux": "^6.0.1",
     "react-router-dom": "^4.3.1",
@@ -26,8 +27,8 @@
   },
   "browserslist": [
     ">0.2%",
+    "ie 11",
     "not dead",
-    "not ie <=11",
     "not op_mini all"
   ]
 }

ServerlessLibraryAPI/ClientApp/src/index.js

@@ -1,3 +1,7 @@
+// These must be the first lines in src/index.js
+import "react-app-polyfill/ie11";
+import "react-app-polyfill/stable";
+
 import "./index.css";
 import React from "react";
 import ReactDOM from "react-dom";