perf(earn): use memoized selectPendingApprovalIds instead of isEqual …

[shane-t]

Replaces the deep-equality-guarded selectPendingApprovals subscription in useMusdConversion with a new createSelector-based selectPendingApprovalIds projection selector. This avoids running lodash isEqual over the entire pending approvals map on every Redux dispatch when the hook only consumes the set of approval IDs.

Description

useMusdConversion subscribed to selectPendingApprovals (the raw pending-approvals map) with a lodash.isEqual comparator, then derived Object.keys(pendingApprovals ?? {}) via useMemo. Since the hook only ever consumes the approval IDs, the deep comparison of the entire approvals map on every Redux dispatch was unnecessary overhead — a band-aid for a missing memoized projection selector.

Changelog

CHANGELOG entry: null

Related issues

Fixes: #31337

Manual testing steps

Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]

Screenshots/Recordings

Before

N/A

After

N/A

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• I've completed the PR template to the best of my ability
• I've included tests if applicable
• I've documented my code using JSDoc format if applicable
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Performance checks (if applicable)

• I've tested on Android
  • Ideally on a mid-range device; emulator is acceptable
• I've tested with a power user scenario
  • Use these power-user SRPs to import wallets with many accounts and tokens
• I've instrumented key operations with Sentry traces for production performance metrics
  • See trace() for usage and addToken for an example

For performance guidelines and tooling, see the Performance Guide.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

---

Note

Low Risk
Behavior-preserving selector refactor in a feature-flagged Earn hook with no auth, payment, or shared controller API changes.

Overview
useMusdConversion no longer subscribes to the full pending-approvals map with lodash.isEqual. It now uses a local createSelector projection, selectPendingApprovalIds, that derives Object.keys from selectPendingApprovals so useSelector can use default reference equality and skip deep compares on every Redux dispatch when only approval IDs matter.

Unit tests cover key extraction, empty state, and stable vs. new array references when the underlying map is unchanged or updated. The selector stays in the hook file rather than approvalController selectors to keep the change scoped to Earn/mUSD.

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[metamask-ci]

PR template — items to address before "Ready for review"

Warnings — informational, address before merging:

• Manual testing steps still contain template content (the Gherkin example title or a [...] placeholder). Replace with real steps, or write N/A — <reason>.
• Pre-merge author checklist has unchecked items (e.g. "I've followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards."). Every box must be consciously checked — see docs/readme/ready-for-review.md.

See docs/readme/ready-for-review.md for the full Definition of Ready for Review.

[github-actions]

🔍 Smart E2E Test Selection

• Selected E2E tags: None (no tests recommended)
• Selected Performance tags: None (no tests recommended)
• Risk Level: low
• AI Confidence: 95%

click to see 🤖 AI reasoning details

E2E Test Selection:
The PR contains two files, both within the Earn/hooks directory:

1. useMusdConversion.ts: A pure internal optimization refactor. The change replaces useSelector(selectPendingApprovals, isEqual) + useMemo(() => Object.keys(...)) with a createSelector-based memoized selector selectPendingApprovalIds. This is functionally equivalent — the same data (pending approval IDs) is derived, just using reselect's structural memoization instead of lodash deep equality + useMemo. The code comment explicitly states "the mUSD conversion feature is flagged off," meaning this code path is not active in production. No UI changes, no API changes, no behavioral changes.

2. useMusdConversion.test.ts: Adds unit tests for the new selectPendingApprovalIds selector — tests reference stability and correctness of the selector. No E2E test infrastructure changes.

Since:

• The mUSD conversion feature is feature-flagged off
• The change is a pure selector memoization optimization with no functional difference
• No user-facing flows are affected
• No shared components (navigation, modals, confirmations) are touched
• No E2E smoke tests cover this specific internal hook

No E2E smoke tags are warranted. No performance tags are warranted either — this is a micro-optimization to selector memoization that would not measurably affect any of the performance test scenarios.

Performance Test Selection:
The change is a selector memoization optimization (reselect createSelector replacing lodash isEqual + useMemo) in a feature-flagged-off mUSD conversion hook. While it's a performance improvement, it's scoped to a disabled feature and would not measurably affect any of the available performance test scenarios (AccountList, Onboarding, Login, Swaps, Launch, AssetLoading, Predict, Perps).

View GitHub Actions results

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 84.39%. Comparing base (c4cb337) to head (f044975).
⚠️ Report is 16 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #33181      +/-   ##
==========================================
+ Coverage   84.37%   84.39%   +0.01%     
==========================================
  Files        6127     6132       +5     
  Lines      163530   163730     +200     
  Branches    39887    39925      +38     
==========================================
+ Hits       137974   138175     +201     
+ Misses      16050    16044       -6     
- Partials     9506     9511       +5     

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud