fix: linting issue

Author: m0-hassan

src/js/07-night-mode.js

@@ -1,23 +1,25 @@
+/* eslint-env browser */
 ;(function () {
-  'use strict'
+  'use strict';
 
-  var currentTheme = localStorage.getItem('theme') || 'light'
-  document.documentElement.setAttribute('data-theme', currentTheme)
+  const storage = (typeof window !== 'undefined' && window.localStorage) ? window.localStorage : null;
+  const currentTheme = storage ? (storage.getItem('theme') || 'light') : 'light';
+  document.documentElement.setAttribute('data-theme', currentTheme);
 
-  function bind() {
-    var toggle = document.querySelector('.night-mode-toggle')
-    if (!toggle) return
-    toggle.addEventListener('click', function () {
-      var next = document.documentElement.getAttribute('data-theme') === 'dark' ? 'light' : 'dark'
-      document.documentElement.setAttribute('data-theme', next)
-      localStorage.setItem('theme', next)
-    })
+  function bind () {
+    const toggle = document.querySelector('.night-mode-toggle');
+    if (!toggle) return;
+    toggle.addEventListener('click', function (e) {
+      e.preventDefault();
+      const next = document.documentElement.getAttribute('data-theme') === 'dark' ? 'light' : 'dark';
+      document.documentElement.setAttribute('data-theme', next);
+      if (storage) storage.setItem('theme', next);
+    });
   }
 
-  // Ensure the button exists before binding
   if (document.readyState === 'loading') {
-    document.addEventListener('DOMContentLoaded', bind)
+    document.addEventListener('DOMContentLoaded', bind);
   } else {
-    bind()
+    bind();
   }
-})()
+})();