add polyfill for String.includes

Author: MartinMalinda

app/initializers/add-string-includes-polyfill.js

@@ -0,0 +1,23 @@
+export function initialize() {
+
+  // Source: https://developer.mozilla.org/cs/docs/Web/JavaScript/Reference/Global_Objects/String/includes#Polyfill
+  if (!String.prototype.includes) {
+    String.prototype.includes = function(search, start) {
+      'use strict';
+      if (typeof start !== 'number') {
+        start = 0;
+      }
+      
+      if (start + search.length > this.length) {
+        return false;
+      } else {
+        return this.indexOf(search, start) !== -1;
+      }
+    };
+  }
+}
+
+export default {
+  name: 'add-string-includes-polyfill',
+  initialize
+};