Handle corrupt and unavailable saving
See this course’s project requirements
A fictional local reading-list app with versioned saved data, explicit browser-only wording, validated JSON export/import and corrupt-save recovery tests.
Keep your working files in your own notebook or software. Save a private description, checklist, and work link in My Proof.
What to include
- Document the exact storage origin and distinguish reload persistence from account synchronization.
- Retain the validated envelope format and prove an invalid replacement leaves the earlier record intact.
- Demonstrate a rejected corrupt load and a failed write without silently discarding prior data.
- Create and inspect an actual JSON export and state its exact contents.
- Produce a valid/invalid import matrix proving rejected content retains the previous list.
- Deliver a two-tab observation or truthful unavailable note, alongside the validated backup/recovery project.
Review and revise
Use these criteria to check your work and choose what to improve.
- The implementation or declared simulation follows the supplied contract and retains inspectable original inputs.
- Normal, boundary and rejected cases are recorded with expected versus observed results.
- The changed case has a correct explanation and does not rely on hidden state.
- The project includes source, outputs, instructions and honest tool, privacy and verification limits.
Want more background?
The idea in everyday life
Use the supplied reading.html, reading-store.mjs and test-reading.mjs with the invented title Moon Garden. Serve the folder at http://localhost:8765 using python3 -m http.server 8765 --bind 127.0.0.1.
A storage read or write can fail; the app must name the failure and preserve the recoverable draft rather than claim a save occurred.
Handle corrupt and unavailable saving — original worked practice
A storage read or write can fail; the app must name the failure and preserve the recoverable draft rather than claim a save occurred.
Use the supplied reading.html, reading-store.mjs and test-reading.mjs with the invented title Moon Garden. Serve the folder at http://localhost:8765 using python3 -m http.server 8765 --bind 127.0.0.1.
1. Step 1
Use the browser storage inspector for this local origin to replace life-reading-v1 with the literal text {. Reload.
You should see: The app reports a load problem and blocks additions.
A storage read or write can fail; the app must name the failure and preserve the recoverable draft rather than claim a save occurred.
2. Step 2
Read the catch branch: it does not overwrite the corrupt key with an empty list.
You should see: The failing record remains available for inspection.
A storage read or write can fail; the app must name the failure and preserve the recoverable draft rather than claim a save occurred.
3. Step 3
Run the mock blocked-write assertion in test-reading.mjs.
You should see: The save function surfaces the blocked write.
A storage read or write can fail; the app must name the failure and preserve the recoverable draft rather than claim a save occurred.
4. Step 4
Reset only this list after keeping any desired backup; record observed recovery and scope.
You should see: A corrupt/blocked-save recovery record.
A storage read or write can fail; the app must name the failure and preserve the recoverable draft rather than claim a save occurred.
What to finish
Demonstrate a rejected corrupt load and a failed write without silently discarding prior data.
Watch for this
Calling a failed write saved or clearing unrelated origin keys during recovery.
How can I tell I understand it?
Demonstrate the rule: A storage read or write can fail; the app must name the failure and preserve the recoverable draft rather than claim a save occurred. Use the supplied variant to distinguish a changed result from a broken implementation.
Quick knowledge check
Answer all 3 questions. Get at least 2 right and the lesson completes automatically.
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Answer all 3 questions above and get at least 2 right. You can review the explanations and try again.
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Sources and further reading
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Source & access notes · checked 2026-10-01
Relevant documented module/API behavior inspected during expansion authoring; actual execution evidence is recorded separately. No grant eligibility is established.
Access: Official page retrieved with the web reader on 2026-10-01. Documentation reading does not certify execution in every native tool or browser.
Reuse: Original local practice files, fictional data, worked examples and questions. Concepts paraphrased and linked; source exercises are not copied.
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