[BUGFIX] Internet Explorer 11 exceptions

app.js

@@ -6,6 +6,53 @@ if (!String.prototype.includes) {
   };
 }
 
+if (!String.prototype.startsWith) {
+  String.prototype.startsWith = function (searchString, position) {
+    position = position || 0;
+    return this.substr(position, searchString.length) === searchString;
+  };
+}
+if (!String.prototype.repeat) {
+  String.prototype.repeat = function (count) {
+    'use strict';
+    if (this === null) {
+      throw new TypeError('can\'t convert ' + this + ' to object');
+    }
+    var str = '' + this;
+    count = +count;
+    if (count < 0) {
+      throw new RangeError('repeat count must be non-negative');
+    }
+    if (count === Infinity) {
+      throw new RangeError('repeat count must be less than infinity');
+    }
+    count = Math.floor(count);
+    if (str.length === 0 || count === 0) {
+      return '';
+    }
+    // Ensuring count is a 31-bit integer allows us to heavily optimize the
+    // main part. But anyway, most current (August 2014) browsers can't handle
+    // strings 1 << 28 chars or longer, so:
+    if (str.length * count >= 1 << 28) {
+      throw new RangeError('repeat count must not overflow maximum string size');
+    }
+    var rpt = '';
+    for (; ;) {
+      if ((count & 1) === 1) {
+        rpt += str;
+      }
+      count >>>= 1;
+      if (count === 0) {
+        break;
+      }
+      str += str;
+    }
+    // Could we try:
+    // return Array(count + 1).join(this);
+    return rpt;
+  };
+}
+
 require.config({
   baseUrl: 'lib',
   paths: {