When you're working on an HTML HTTP val in a new tab, it's annoying to have to manually reload the tab on every save. In the Val Town editor, you can hit cmd+enter, but there's nothing like that for a val in a new tab because Val Town doesn't control that new tab (like we control the iframe in the browser preview). However, you control that HTML via the fetch handler you're writing, so you can add a script that polls the Val Town API for the current version number of your val, and reload itself if it detects a new version. This val has a collection of helpers to help you do just that.

Create val
import { html } from "https://esm.town/v/stevekrouse/html";
import { reloadOnSaveFetchMiddleware } from "https://esm.town/v/stevekrouse/reloadOnSave";

export default reloadOnSaveFetchMiddleware(async function(req: Request): Promise<Response> {
  return html(`<h1>Hello!!</h1>`);
})