A null key is cached instead of font-size on initial page load

[rdipardo]

Describe the bug

On page load, core.js looks in local storage for a font size:

clean-jsdoc-theme/static/scripts/core.js

Lines 408 to 418 in a69b404

	if (fontSizeInLocalStorage) {
	var n = Number.parseInt(fontSizeInLocalStorage, 10);
	if (n === fontSize) {
	return;
	}
	updateFontSize(n);
	} else {
	localStorage.setItem(fontSizeInLocalStorage, fontSize);
	}
	})();

When storage is empty, a key of null is returned and then stored with the current font size value:

The null entry is never updated, because clicking the "Change font size" button creates a new, proper key:

To Reproduce

1. Go to https://ankdev.me/clean-jsdoc-theme/v4/
2. Open the Developer Tools panel (F12 or Ctrl+Shift+I
3. Select the Application tab and inspect Local Storage for the https://ankdev.me domain
4. A null key has the value 16

Expected behavior

A font-size key has the value 16

Screenshots

See description above

Desktop (please complete the following information):

• OS: Linux 4.19.0-20-amd64 #1 SMP Debian 4.19.235-1 (2022-03-17) x86_64 GNU/Linux
• Browser: Opera
• Version: 88.0.4412.40

Additional context

This change will ensure the font size key is always a valid string:

--- a/static/scripts/core.js
+++ b/static/scripts/core.js
@@ -413,7 +413,7 @@ function updateFontSize(fontSize) {
     }
     updateFontSize(n);
   } else {
-    localStorage.setItem(fontSizeInLocalStorage, fontSize);
+    localStorage.setItem(fontSizeLocalStorageKey, fontSize);
   }
 })();
 

[ankitskvmdam]

Thanks, @rdipardo, it is beautiful that you have spotted this issue.