Bug: Improve back navigation logic in ItemComponent

[milanmajchrak]

References

• Port of ufal/dspace-angular#80
• Related bug reports:
  • ufal/dspace-angular/issues/63
  • ufal/dspace-angular#106

Original author: @amadulhaxxani

Description

Improves the "Back to results" button logic on item pages by adding session storage as a fallback for the previous URL. This ensures the back button works correctly across page refreshes and prevents stale navigation when users visit items from different contexts (e.g. homepage vs. collection browse).

Instructions for Reviewers

List of changes in this PR:

• Added storeUrlInSession() and getUrlFromSession() generic helper methods to RouteService for persisting URLs in session storage
• Updated ItemComponent to store the previous URL in session storage and fall back to it when the route-based previous URL is not a valid navigation target
• Added /home to the list of allowed previous routes so the back button appears when navigating from the homepage
• Extracted URL validation into a pickAllowedPrevious() helper method for cleaner logic
• Simplified the back() method to use the stored URL directly instead of re-subscribing to the observable
• Updated test stubs and mocks in route-service.stub.ts, publication.component.spec.ts, untyped-item.component.spec.ts, and item.component.spec.ts
• Added new test cases for home URL back navigation and for prioritizing the current route URL over stale session storage

How to test:

1. Go to a collection page and click on an item — you should see "Back to results"; clicking it returns you to the collection
2. Refresh the item page — the "Back to results" button should still appear (session storage fallback)
3. Navigate to the homepage, click an item from "What's New" — you should see "Back to results" pointing to the homepage
4. Regression check: From a collection, open an item. Then go to the homepage and open a different item. The back button should now point to the homepage, not to the previous collection

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[Copilot]

Pull request overview

Improves “Back to results” navigation on item pages by persisting an allowed previous URL in session storage, so the back button remains correct across refreshes and different navigation entry points (including /home).

Changes:

• Added generic session storage URL helpers to RouteService.
• Updated ItemComponent to validate/store previous URLs and fall back to session storage when route history isn’t usable; expanded allowed previous routes to include /home.
• Updated/added unit tests and stubs to cover the revised behavior.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/app/core/services/route.service.ts	Adds sessionStorage helpers for storing/retrieving URLs.
src/app/item-page/simple/item-types/shared/item.component.ts	Stores/uses a validated previous URL with a session fallback; allows /home.
src/app/item-page/simple/item-types/shared/item.component.spec.ts	Adds tests for /home back navigation and “prefer route over stale session” behavior.
src/app/core/testing/route-service.stub.ts	Extends the RouteService stub with session helper methods for tests.
src/app/item-page/simple/item-types/publication/publication.component.spec.ts	Updates RouteService mocks to include new session helper methods.
src/app/item-page/simple/item-types/untyped-item/untyped-item.component.spec.ts	Updates RouteService mocks to include new session helper methods.

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[alegontarz]

QA testing performed (no code review).

Works as expected:

1. "Back to results" correctly navigates to the previous page — the button points to the most recent valid route.
2. After page refresh, the button remains visible and works.

[github-actions]

Hi @milanmajchrak,
Conflicts have been detected against the base branch.
Please resolve these conflicts as soon as you can. Thanks!

[tdonohue]

@milanmajchrak : Could you resolve the merge conflict on this PR so that we are able to move this forward? Thanks!

[milanmajchrak]

@milanmajchrak : Could you resolve the merge conflict on this PR so that we are able to move this forward? Thanks!

@tdonohue Thank you for the reminder.

The merge conflicts have been resolved and the branch has been cleaned up into a single commit.
At this point, the only remaining issue is one failing unit-test job on tests (20.x), which appears to be flaky:
it passes locally (including repeated runs), and the tests (22.x) job passes in CI.