Pages Editor: implement Delete Page action

[shaunanoordin]

PR Overview

Part of: Pages Editor MVP project and FEM Lab super-project Follows #6991 Staging branch URL: https://pr-7046.pfe-preview.zooniverse.org/lab/1982/workflows/editor/3711?env=staging

This PR adds the ability to delete a Step/Page.

• Clicking on the "trash can" icon on a Page will prompt a confirmation dialog, before deleting a Step/Page.
• Any Branching Task with answers that pointed to the now-deleted Page will be updated, so the answers now point to nothing (i.e. "Submit").
  • A new cleanupTasksAndSteps() helper function has been added to remove orphaned references in branching tasks, (this has been implemented). This maaay be updated in the future to also remove Tasks that aren't associated with any Steps, and remove Steps that have 0 Tasks. We'll see.

Other changes:

• Fixed an issue where deleting Answers in a Single Question Task (by clicking on the "minus" button) didn't actually register changes.

Notes:

• ⚠️ The "Preview Workflow" button is still hardcoded to WF 3711. Shaun: please remember to fix this by loading the Project resource in DataManager in the next PR.

Status

Ready for review!

[coveralls]

coverage: 56.98%. remained the same when pulling 0257819d352cbd34a82f849575ecef05c70d654f on pages-editor-pt14 into 3c979c8d1048a210ce230726adaeda7cc9017c3c on master.

[shaunanoordin]

PR Update

• Bug & Fix: deleting Pages caused invalid values to persist in the previous step's stepX.next. cleanupTasksAndSteps() has now been updated to also call linkStepsInWorkflow() to ensure linked pages remain valid.

[shaunanoordin]

I can't believe I forgot to add in a Testing section.

Testing

In this PR, we're testing the "Delete Pages" action. (Dev Reminder: pages == steps. "Page" is what the volunteer sees. "step" is what's in the code.)

Testing steps:

• Open the testing URL. You should be viewing the Tasks of a test Workflow (e.g. staging WF 3711), on the Pages Editor.
• Create a simple workflow with multiple Pages, with at least one branching Page.
  • (For convenience, a "Quick Setup" button is available in the debug panel at the bottom of the page.)
• Click on the Delete button (trashcan icon) to delete a Page. There should be a confirmation dialog before this happens, tho.
  • Expectation 1: the Page and all its Tasks should be removed from the workflow.
  • e.g. when deleting page P0 with task T0, check that workflow.tasks and workflow.steps in the Workflow resource have P0 and T0 removed. This can only be checked via observing network requests or inspecting the resource.
  • Expectation 2: "Any task.next = deletedPage should become task.next = undefined". Any branching options that pointed to a now-deleted Page should now point to "Submit". This should be visible immediately on the Pages Editor.
  • Expectation 3: "Any step.next = deletedPage should become step.next = undefined". Any non-branching Page automatically point to the next Page in the sequence. If P2 -> P3 -> P4, and P3 is deleted, the sequence of pages should now be P2 -> P4. This can be tested by classifying the workflow.

❗ Basically, the big hidden rule that Expectations 1 to 3 attempts to codify is that, when you delete a Page and all its Tasks, then ALL SECONDARY REFERENCES to that Page and Task should ALSO be nuked, and the workflow should continue working as if they never existed.

Example: a 3 Page workflow created via Quick Setup. The first page (with T0) is a branching Page that points to the second page (with T1) and the third page (with T2).

[shaunanoordin]

Thanks Travis! 👍

Might be useful to create a document of interesting edge cases / concerns / outline of all useful tests to be written when this gets migrated to FEM.

Ooo good point, I'm going to need to bring up the idea of starting this doc, to Sam & Sean next Monday.