Added code for on hash change

src/index.ts

···
         el.classList.add('active');
     }
 };
+
+window.onhashchange = (event: HashChangeEvent) => {
+    const oldHash = event.oldURL.substr(event.oldURL.indexOf('#') + 1);
+    const newHash = event.newURL.substr(event.newURL.indexOf('#') + 1);
+    const oldEl: HTMLElement | null = document.getElementById(oldHash + '-page');
+
+    if (oldEl === null) {
+        document.getElementById('home-page')!.classList.remove('active');
+    } else {
+        oldEl.classList.remove('active');
+    }
+
+    const el: HTMLElement | null = document.getElementById(newHash + '-page');
+
+    if (el === null) {
+        document.getElementById('home-page')!.classList.add('active');
+    } else {
+        el.classList.add('active');
+    }
+};