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

Checklist

This checklist provides a reminder of what we are going to look for when reviewing your PR. You do not need to complete this checklist prior creating your PR (draft PRs are always welcome).
However, reviewers may request that you complete any actions in this list if you have not done so. If you are unsure about an item in the checklist, don't hesitate to ask. We're here to help!

• My PR is created against the main branch of code (unless it is a backport or is fixing an issue specific to an older branch).
• My PR is small in size (e.g. less than 1,000 lines of code, not including comments & specs/tests), or I have provided reasons as to why that's not possible.
• My PR passes ESLint validation using npm run lint
• My PR doesn't introduce circular dependencies (verified via npm run check-circ-deps)
• My PR includes TypeDoc comments for all new (or modified) public methods and classes. It also includes TypeDoc for large or complex private methods.
• My PR passes all specs/tests and includes new/updated specs or tests based on the Code Testing Guide.
• My PR aligns with Accessibility guidelines if it makes changes to the user interface.
• My PR uses i18n (internationalization) keys instead of hardcoded English text, to allow for translations.
• My PR includes details on how to test it. I've provided clear instructions to reviewers on how to successfully test this fix or feature.
• If my PR includes new libraries/dependencies (in package.json), I've made sure their licenses align with the DSpace BSD License based on the Licensing of Contributions documentation.
• If my PR includes new features or configurations, I've provided basic technical documentation in the PR itself.
• If my PR fixes an issue ticket, I've linked them together.

[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.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[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.

[tdonohue]

👍 Thanks @milanmajchrak ! I've verified this works well & the code looks good to me. I'm also going to flag this for possible backport to dspace-9_x because I agree it's a usability improvement.

[dspace-bot]

Backport failed for dspace-9_x, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin dspace-9_x
git worktree add -d .worktree/backport-5170-to-dspace-9_x origin/dspace-9_x
cd .worktree/backport-5170-to-dspace-9_x
git switch --create backport-5170-to-dspace-9_x
git cherry-pick -x c6f6ae28b565598857c04e08df0b97e5c009752c

[tdonohue]

@milanmajchrak : It looks like the automated backport to 9.x failed (see above). If you'd like to see this in 9.x, please create a separate PR against our dspace-9_x branch and assign it to me for review. Otherwise, we'll just see this usability improvement in 10.0

[tdonohue]

Backported to 9.x in #5631