Offline-first PWA

What it is

Digital evaluation is an offline-first PWA (Progressive Web App). That means:

• It opens like a normal web page (it's not a store app).
• Once open, it keeps working even if you lose your connection.
• When the connection comes back, it automatically syncs the data to the server.

Why it matters

A chocolatier's workshop doesn't always have a good connection: cold rooms with thick walls, basements, industrial kitchens with limited WiFi. A tool that crashes whenever coverage drops out is unworkable in practice.

How it works

First open (with a network)

1. The panelist opens the unique link. The PWA downloads and is cached in their browser.
2. Basic tasting data (samples, protocol, attributes) downloads as well.
3. From this point on, the panelist can work even if the connection drops.

During the evaluation (with or without a network)

• Every change is saved locally on the device (IndexedDB / Dexie).
• If there's a network, the changes are sent to the server immediately.
• If there's no network, the changes pile up locally and are sent as soon as the connection comes back.

After sending

• When the panelist taps Confirm and send at the end, the evaluation is marked as completed locally.
• As soon as the device gets a network again, the evaluation uploads to the server and shows up as completed in the leader's tasting detail.

Status indicator

Below the header, the panelist sees a small pill showing the save and sync status. When everything is up to date and there's a connection, the pill hides itself. The states it can show are:

• Saving… — the change is being saved on the device.
• Syncing… / Syncing N pending… — the changes are being sent to the server.
• Offline — no network and nothing pending to send.
• Offline · N saved locally — no network, with changes saved on the device waiting to upload.
• Sync error — something failed while uploading; try again when you have a stable network.

There is no state labeled "Saved": when there's a connection and nothing pending, the pill simply disappears.

What happens if I close the browser

• The data is saved locally. When you open the link again on the same device and the same browser, you get the in-progress evaluation back.
• If you switch devices before syncing, the data on the first device stays there until you reopen it. To avoid losing data: finish the evaluation on the same device where you started it, and make sure you have a network at the end so it can sync.

Honest limitations

• The first open requires a connection to download the PWA and the tasting data.
• Syncing to the server needs a connection (the app can't read minds).
• If you close the browser, you lose the session and the cookie — but the data persists in IndexedDB until you reopen the same link.