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 time opening the link (online)

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. Once the tasting is saved on the phone, the welcome screen says so with the notice Ready to taste offline.

During the evaluation (online or offline)

• Each sample is saved when you tap Save and back to selector. If there's a network, it's sent to the server right then.
• If there's no network, the sample stays saved on the device (IndexedDB) and is sent on its own as soon as the connection comes back; while there are pending saves, the app retries every 30 seconds.
• If the panelist opens the sheet offline and the phone has a copy of the tasting, they see the notice "Offline: you're tasting from the copy saved on this phone. What you score will be sent on its own as soon as coverage returns."

After sending

• The panelist sends the evaluation with Confirm and send: in the descriptive tasting and the tests scored sample by sample, that button is on the review screen (reached with Review and send); in triangle, paired comparison, duo-trio, and ranking tests it's on the sheet itself, and the submission is then confirmed with Send definitively. If there's no network at that moment, the final screen shows Waiting to be sent: the evaluation is recorded on the phone.
• 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. If you open the link offline on a device that has no copy, you'll see "You're offline and there's no copy of this tasting on this phone…". 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

• Opening the link for the first time 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.