Multi select on shift+click

[ellatrix]

Not to be confused with shift+arrow keys, which will be addressed in a different PR.

With this PR you can multi-select block by pressing shift and then clicking. At the moment you can only select by clicking and dragging while holding the click. See #2990.

To test:

• Select a block.
• Press shift and click on another block. There should be a multi-selection with both these blocks and all blocks in between.
• Click again on a block further away from the first block you selected. Multi-selection should now have extended to the last clicked block.
• Now click on a block closer to the one you first selected, inside the multi-selection. Multi-selection should now have shrunk form the initial selected block to the last clicked block.
• Verify that shift+click still works in an editable area.

[aduth]

One UX change to confirm is: When no blocks are selected, and I shift-click a block, nothing happens. Previous to these changes, the text in the block would still highlight (using default browser behavior, I assume).

Also generally don't feel that this addresses usability flows noted in #179. I can describe more there, but I expect to be able to extend partial selection between paragraphs and either backspace to collapse or start typing to replace. Multi-select doesn't allow for this, really only entire delete and rearrangement.

[mcsf]

This tests well for me, and the logic is clear. Nice. :)

[mcsf]

It's beside the object of this PR, but I'll share the note: we probably shouldn't be binding (and re-binding) these methods before passing them to VisualEditorBlock instances — they're all grown up and can do that themselves in the constructor, or just pass their uid explicitly. :)

[mcsf]

Would be nice to have a more descriptive name for onSelectionExtension, but I don't know what that could be. :) I know they are controversial, but I like maybe-prefixed names, like maybeMultiSelect, but that clashes with the on- framing. onShiftSelection?

[ellatrix]

Hm, maybe seems strange because something always happens. I don't mind onShiftSelection.

[codecov]

Codecov Report

Merging #1965 into master will increase coverage by 0.45%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #1965      +/-   ##
==========================================
+ Coverage    33.4%   33.85%   +0.45%     
==========================================
  Files         197      197              
  Lines        5778     6037     +259     
  Branches     1023     1098      +75     
==========================================
+ Hits         1930     2044     +114     
- Misses       3247     3348     +101     
- Partials      601      645      +44

Impacted Files	Coverage Δ
editor/modes/visual-editor/block.js	0% <0%> (ø)	⬆️
editor/modes/visual-editor/block-list.js	0% <0%> (ø)	⬆️
blocks/library/gallery/block.js	9.75% <0%> (-1.36%)	⬇️
blocks/library/table/table-block.js	7.4% <0%> (-0.6%)	⬇️
editor/block-settings-menu/content.js	0% <0%> (ø)	⬆️
editor/block-toolbar/index.js	0% <0%> (ø)	⬆️
editor/block-settings-menu/index.js	0% <0%> (ø)	⬆️
editor/block-switcher/index.js	0% <0%> (ø)	⬆️
utils/focus/tabbable.js	100% <0%> (ø)	⬆️
blocks/library/image/block.js	0% <0%> (ø)	⬆️
... and 6 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 65b43ca...e2a6fa2. Read the comment docs.

[gziolo]

That was fast, thanks for implementing this one 😄

Edit: I see now, it was opened for weeks :)