Removed support for IE totally.

Added error message displayed in IE.

package.json

@@ -3,19 +3,17 @@
   "version": "1.0.0",
   "main": "src/index.tsx",
   "dependencies": {
-    "array.prototype.find": "^2.0.4",
     "d3": "^5.7.0",
+    "detect-browser": "^4.1.0",
     "history": "^4.7.2",
     "md5": "^2.2.1",
     "query-string": "^5.1.1",
     "react": "latest",
-    "react-app-polyfill": "^0.2.0",
     "react-dom": "latest",
     "react-intl": "^2.8.0",
     "react-router-dom": "^4.3.1",
     "semantic-ui-css": "^2.4.1",
     "semantic-ui-react": "^0.84.0",
-    "string.prototype.startswith": "^0.2.0",
     "topola": "^2.2"
   },
   "devDependencies": {
@@ -47,7 +45,7 @@
   "browserslist": [
     ">0.2%",
     "not dead",
-    "not ie < 11",
+    "not ie <= 11",
     "not op_mini all"
   ]
 }

src/index.tsx

@@ -1,12 +1,10 @@
-import 'react-app-polyfill/ie11';
-import 'string.prototype.startswith';
-import 'array.prototype.find';
 import * as locale_en from 'react-intl/locale-data/en';
 import * as locale_pl from 'react-intl/locale-data/pl';
 import * as React from 'react';
 import * as ReactDOM from 'react-dom';
 import messages_pl from './translations/pl.json';
 import {addLocaleData} from 'react-intl';
+import {detect} from 'detect-browser';
 import {ChartView} from './chart_view';
 import {HashRouter as Router, Route, Switch} from 'react-router-dom';
 import {IntlProvider} from 'react-intl';
@@ -22,6 +20,17 @@ const messages = {
 };
 const language = navigator.language && navigator.language.split(/[-_]/)[0];
 
+const browser = detect();
+
+if (browser && browser.name === 'ie') {
+  ReactDOM.render(
+    <p>
+      Topola Genealogy Viewer does not support Internet Explorer. Please try a
+      different browser.
+    </p>,
+    document.querySelector('#root'),
+  );
+} else {
   ReactDOM.render(
     <IntlProvider locale={language} messages={messages[language]}>
       <Router>
@@ -36,3 +45,4 @@ ReactDOM.render(
     </IntlProvider>,
     document.querySelector('#root'),
   );
+}