I built this JavaScript Counter App with Persistent Local Storage on my own after reviewing a similar one in a tutorial which I did not like. I also added additional features like the Reset button and Save to local storage. You can use the developer module in your web browser to view the console results as you run the app.
It is a proof of concept because we would most likely use a more permanent storage on the Server Side (vs. the Client Side) for a real web app.
Here is a link to the zipped website with the html, css, javascript, and image files. “Subway Counter App with Persistent Storage”