add polyfills for .matches and .closest

web/app/app.js

@@ -1,4 +1,8 @@
+import 'babel-polyfill'; // TODO: remove it
 import 'mimic'; // TODO: it's for dev only
+
+import './polyfills'; // TODO: check it
+
 import fetcher from './fetcher';
 import render from './render';
 
@@ -7,5 +11,5 @@ require('./main.scss');
 // TODO: add preloader
 // TODO: all of these settings must be optional params
 fetcher
-  .get('/find?site=remark&url=https://radio-t.com/p/2017/12/16/podcast-576/&sort=time&format=tree')
+  .get('/find?url=https://radio-t.com/p/2017/12/16/podcast-576/&sort=time&format=tree')
   .then(render);

web/app/polyfills.js

@@ -0,0 +1,14 @@
+if (!Element.prototype.matches)
+  Element.prototype.matches = Element.prototype.msMatchesSelector ||
+    Element.prototype.webkitMatchesSelector;
+
+if (!Element.prototype.closest)
+  Element.prototype.closest = function(s) {
+    var el = this;
+    if (!document.documentElement.contains(el)) return null;
+    do {
+      if (el.matches(s)) return el;
+      el = el.parentElement || el.parentNode;
+    } while (el !== null);
+    return null;
+  };