Migrate secondary side panels to Angular Signals #2420

rfontanarosa · 2026-01-30T17:04:56Z

closes #1669
towards #2256

Registrazione.schermo.2026-01-30.alle.18.00.45.mov

gemini-code-assist · 2026-01-30T17:05:22Z

Summary of Changes

Hello @rfontanarosa, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request significantly modernizes the implementation of the secondary side panels by adopting Angular Signals. The change aims to improve the reactivity, maintainability, and performance of these components by moving away from traditional RxJS subscriptions for state management. This refactoring simplifies the component logic and aligns with the latest Angular best practices for reactive programming.

Highlights

Angular Signals Migration: The secondary side panels, specifically the Location of Interest (LOI) panel and the Submission panel, have been refactored to utilize Angular Signals for state management. This involves converting component properties and data streams into signals and computed signals.
Simplified Component Lifecycle: The OnInit and OnDestroy lifecycle hooks, along with manual Subscription management, have been removed from LoiPanelComponent and SubmissionPanelComponent. Data fetching and reactivity are now handled declaratively using toSignal and computed.
Template Updates: HTML templates for both loi-panel and submission-panel have been updated to reflect the signal-based approach, calling signals as functions (e.g., isLoading() instead of isLoading). Internationalization (i18n) attributes were also added to some static text.
Enhanced Testability: Unit tests for LoiPanelComponent and SubmissionPanelComponent have been updated to incorporate fakeAsync and tick from @angular/core/testing, ensuring proper testing of asynchronous operations and signal updates.
Improved Coordinate Formatting: The SubmissionPanelComponent now uses internationalized labels for displaying coordinate information (e.g., 'E'/'W', 'N'/'S', 'Altitude', 'Accuracy'), making the UI more adaptable to different languages.

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codecov-commenter · 2026-01-30T17:07:43Z

Codecov Report

❌ Patch coverage is 76.66667% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.53%. Comparing base (f389d7b) to head (cfe49ba).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...nel/submission-panel/submission-panel.component.ts	71.42%	10 Missing and 2 partials ⚠️
...ondary-side-panel/loi-panel/loi-panel.component.ts	88.88%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2420      +/-   ##
==========================================
- Coverage   59.58%   59.53%   -0.06%     
==========================================
  Files         111      111              
  Lines        2769     2768       -1     
  Branches      405      408       +3     
==========================================
- Hits         1650     1648       -2     
- Misses       1061     1063       +2     
+ Partials       58       57       -1

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gemini-code-assist

Code Review

This pull request migrates secondary side panels to use Angular Signals, which is a great step towards modernizing the application's state management. The changes are generally well-implemented, but there are a few critical issues and areas for improvement that I've identified. Specifically, there are potential null pointer exceptions in templates due to how signals are handled, a bug in a component method where a signal is not being accessed correctly, and some anti-patterns like side effects within signal definitions. I've provided detailed comments and suggestions for each of these points.

...onents/main-page-container/main-page/secondary-side-panel/loi-panel/loi-panel.component.html

gemini-code-assist · 2026-01-30T17:08:07Z

...mponents/main-page-container/main-page/secondary-side-panel/loi-panel/loi-panel.component.ts

+      switchMap(([survey, lois, loiId]) => {
+        const loi = lois?.find(l => l.id === loiId);
+        if (survey && loi) {
+          console.log(loiId);
+          this.iconColor = survey.getJob(loi.jobId)?.color ?? '';
+          this.loi = loi;
+          this.name = LocationOfInterestService.getDisplayName(loi);
+          this.icon = getLoiIcon(loi);
+          return concat(
+            of(undefined),
+            this.submissionService.getSubmissions$(survey, loi).pipe(delay(100))
+          );
+        }
+        return of(null).pipe(delay(100));
+      })


This switchMap has a couple of issues:

It contains a console.log which should be removed.

It has side effects by modifying component properties (iconColor, loi, name, icon). This is an anti-pattern when working with signals, as it makes data flow implicit and harder to track.

A better approach would be to use computed signals to derive these properties from your inputs. This makes your component more declarative and aligned with the signal-based mindset.

...page-container/main-page/secondary-side-panel/submission-panel/submission-panel.component.ts

gino-m · 2026-01-30T18:41:04Z

...page-container/main-page/secondary-side-panel/submission-panel/submission-panel.component.ts

+    return this.submission() === undefined;
+  });
+
+  submission = toSignal(


Same question here.

gino-m · 2026-01-30T18:41:47Z

...mponents/main-page-container/main-page/secondary-side-panel/loi-panel/loi-panel.component.ts

-        })
-    );
-  }
+  submissions = toSignal(


Why do we need signals at all? Can't the loi and survey just be a component inputs? This seems much more complicated..

…lay-when-selecting-lois

…cting-lois' of https://github.com/google/ground-platform into rfontanarosa/1669/submission-list-brief-delay-when-selecting-lois

secondary panel migrated to signal + loading spinner

c17bcaa

rfontanarosa self-assigned this Jan 30, 2026

rfontanarosa requested a review from gino-m January 30, 2026 17:05

gemini-code-assist bot reviewed Jan 30, 2026

View reviewed changes

gino-m requested changes Jan 30, 2026

View reviewed changes

rfontanarosa added 4 commits January 31, 2026 19:08

remove: console.log + duplicate if statement

f4b71a5

Merge branch 'master' into rfontanarosa/1669/submission-list-brief-de…

3f83433

…lay-when-selecting-lois

added a check because submissions can be null

76a74e0

Merge branch 'rfontanarosa/1669/submission-list-brief-delay-when-sele…

cfe49ba

…cting-lois' of https://github.com/google/ground-platform into rfontanarosa/1669/submission-list-brief-delay-when-selecting-lois

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Migrate secondary side panels to Angular Signals #2420

Migrate secondary side panels to Angular Signals #2420

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rfontanarosa commented Jan 30, 2026

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