Turbo Streams: update document title with a custom action

Sometimes the DOM updates but the browser tab title stays stale (e.g., unread count, active chat room). A neat Hotwire trick is a custom Turbo Stream action that sets document.title. The server emits a <turbo-stream action='set_title'> with a template containing the new title string. On the client, register Turbo.StreamActions.set_title and set document.title accordingly. This keeps the title logic server-side (easy to format, localize, include counts) and avoids sprinkling JS in controllers. I use it sparingly, but it’s very nice for inbox-style apps where the title communicates context. It also pairs well with Turbo Streams that update the visible header on the page.