Offline service notes

Implementation

The browser saves a note and its outgoing operation in one IndexedDB transaction. Attempted operations retain their ID and payload for retry.

The Node API checks visit assignments and base versions, then commits the record change and replay response together in SQLite. A repeated operation returns the original outcome without another version increment.

The interface shows pending, confirmed, conflicted, and rejected records. Conflict review retains both versions, and a JSON export includes saved records, pending operations, and history.

The shell cache handles connection loss and HTTP 503, upgrades its own scoped cache and reports eviction. Snapshot and restore commands verify SQLite integrity, row counts and file digests.

Inputs and assumptions

• Three synthetic service visits and public demo identities are included. Sessions expire 24 hours after database creation.
• A localhost Node.js 24 server and a modern browser with IndexedDB are required. The service-worker shell requires HTTPS or localhost.
• The data model contains text notes and three Boolean checklist fields; it has no photo attachments.

Results

Report figures (2)

Open the full report ↗

Verification

15 HTTP/SQLite tests and 16 separately observed Chrome IndexedDB checks. Added 13 worker-source simulations, 11 real process/recovery checks, five snapshot CLI checks and 10 theoretical deployment cases.

node verify.mjs

Project files

The ZIP contains the source, inputs, results, and instructions. These files are also available individually.

• Node API and SQLite transactionsserver.mjs · 9 KB
• IndexedDB draft and outbox storepublic/store.mjs · 6 KB
• Synchronization protocolpublic/protocol.mjs · 2 KB
• Application interface logicpublic/app.mjs · 6 KB
• HTTP and database teststest-server.mjs · 5 KB
• Executed API test logresults/api-tests.tap · 3 KB
• Recorded browser verificationresults/browser-verification.json · 2 KB
• Setup, usage, and limitsREADME.md · 7 KB
• Extended verification reportcompletion-report.html · 15 KB
• Acceptance matrix and source hashescompletion.json · 17 KB
• Operation, recovery and deployment assessmentOPERATIONS.md · 6 KB
• Worker lifecycle simulationtest-sw.mjs · 8 KB
• Verified SQLite snapshot commandsnapshot.mjs · 2 KB
• Snapshot restore commandrestore.mjs · 2 KB

Run locally

Node.js 24 or newer / SQLite via node:sqlite / Modern browser with IndexedDB

Extract the ZIP and open a terminal in the offline-service-notes folder. The README includes setup and usage details.

node verify.mjs
node server.mjs
# Open http://localhost:8787
node complete.mjs

Limits

• Public fixture tokens are a demonstration mechanism, not production authentication. The server is restricted to localhost.
• Browser storage can be cleared or evicted. Saved records should be synchronized or exported when they must be retained.
• The browser harness uses simulated transport failures; the separate API tests use real HTTP and SQLite. No physical-device or cross-browser test coverage is claimed.
• Secure-context worker installation is represented by an executed lifecycle/cache model; an observed Chrome offline reload is not claimed.
• Remote hosting and identity received a theoretical deployment assessment. The shipped application uses localhost and synthetic identities.