refactor(studio): extract settings persistence to src/prefs.js (step 4)

[byrongamatos]

What

Step 4. Moves _loadSettings / _saveSettings (localStorage-backed user name + selected input device, now reading/writing the S container) into src/prefs.js, imported by the same names. main.js unchanged at the call sites.

Move-only, no behaviour change.

Tests

New tests/prefs.test.mjs (in-memory localStorage stub): round-trip through S, no-op when empty, corrupt-JSON tolerance, and the deviceId !== undefined apply rule. node --test 11/11, pytest 25/25. Codex preflight: 0.

Summary by CodeRabbit

• Chores
  • Refactored settings persistence into a dedicated module and updated the app to use it.
  • Updated the changelog for the ES-module migration step.
• Tests
  • Added automated coverage for saving/loading preferences, including round-trip, empty storage, corrupt data handling, and partial/empty stored values.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 2d67d40e-35f4-4fe8-81da-db587a793f0d

📥 Commits

Reviewing files that changed from the base of the PR and between ec01c21 and ff6eb7c.

📒 Files selected for processing (1)

• tests/prefs.test.mjs

🚧 Files skipped from review as they are similar to previous changes (1)

• tests/prefs.test.mjs

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📝 Walkthrough

Walkthrough

Settings persistence logic is moved from src/main.js into src/prefs.js, and main.js now imports the helpers from that module. New tests cover persistence behavior, and the changelog records the extraction.

Changes

Settings persistence extraction

Layer / File(s)	Summary
New prefs.js module implementing load/save settings src/prefs.js	Adds STORAGE_KEY, _loadSettings(), and _saveSettings() for localStorage-backed settings persistence.
main.js wiring to use prefs.js src/main.js	Imports _loadSettings and _saveSettings from ./prefs.js and removes the inline persistence implementation.
Tests and changelog for prefs extraction tests/prefs.test.mjs, CHANGELOG.md	Adds tests for round-trip, empty storage, corrupt JSON, and partial state handling; updates the changelog entry for the extraction.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main change: extracting settings persistence into src/prefs.js as step 4.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch feat/es-module-split-prefs

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[Copilot]

Pull request overview

Refactors studio settings persistence by extracting the localStorage-backed _loadSettings / _saveSettings logic into a dedicated src/prefs.js module while keeping main.js call sites unchanged, and adds targeted Node test coverage for the persistence behavior.

Changes:

• Added src/prefs.js to own settings load/save logic via the shared S state container.
• Updated src/main.js to import _loadSettings / _saveSettings from src/prefs.js and removed the inline implementations.
• Added tests/prefs.test.mjs and updated CHANGELOG.md to document the migration step.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
tests/prefs.test.mjs	Adds unit tests for settings persistence via S using an in-memory localStorage stub.
src/prefs.js	New module implementing _loadSettings / _saveSettings using S and localStorage.
src/main.js	Switches to importing settings persistence functions from src/prefs.js.
CHANGELOG.md	Documents ES-module migration step 4 and the new prefs tests.

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[coderabbitai]

🧹 Nitpick comments (1)

tests/prefs.test.mjs (1)

45-51: 📐 Maintainability & Code Quality | 🔵 Trivial | ⚡ Quick win

Strengthen "userName left as-is" assertion.

Unlike deviceId, S.userName isn't seeded with a stale sentinel before calling _loadSettings() (it's already '' from beforeEach), so line 50 passes trivially and doesn't actually verify the "left as-is" behavior.

✅ Proposed fix

 test('_loadSettings applies an empty deviceId (deviceId !== undefined) but skips missing userName', () => {
     store.set('slopsmith_studio', JSON.stringify({ deviceId: '' }));
     S.selectedDeviceId = 'stale';
+    S.userName = 'stale';
     _loadSettings();
     assert.equal(S.selectedDeviceId, '');   // '' is applied (!== undefined)
-    assert.equal(S.userName, '');           // absent userName left as-is
+    assert.equal(S.userName, 'stale');      // absent userName left as-is
 });

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@tests/prefs.test.mjs` around lines 45 - 51, The _loadSettings test currently
does not really verify that a missing userName is left unchanged because
S.userName starts as an empty string from beforeEach, so the assertion passes
trivially. Update the test in prefs.test.mjs by seeding S.userName with a
non-empty stale sentinel before calling _loadSettings(), then assert it remains
unchanged when userName is absent from the stored settings, alongside the
existing S.selectedDeviceId check.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@tests/prefs.test.mjs`:
- Around line 45-51: The _loadSettings test currently does not really verify
that a missing userName is left unchanged because S.userName starts as an empty
string from beforeEach, so the assertion passes trivially. Update the test in
prefs.test.mjs by seeding S.userName with a non-empty stale sentinel before
calling _loadSettings(), then assert it remains unchanged when userName is
absent from the stored settings, alongside the existing S.selectedDeviceId
check.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 5321a1a8-e50e-4c5c-8c93-86b9caefbc51

📥 Commits

Reviewing files that changed from the base of the PR and between 9e660b9 and ec01c21.

📒 Files selected for processing (4)

• CHANGELOG.md
• src/main.js
• src/prefs.js
• tests/prefs.test.mjs