bugfix: first multiselection has no _lastSelectedIndex

[frykten]

#787

Should I add a test?

[mixonic]

@frykten Yes this should certainly get a test. I'm a bit surprised the functionality isn't already covered by a test. It is because the tested functionality uses click, then shift+click? And your issue is trigged by shift+click without a preceding click?

[frykten]

@mixonic Yes, that's exactly it.

What would you advise: change the method selectRange() used to select from a normal click first => shift+click second to shift+click first => shift+click second or since both should be available, let's test both?

[mixonic]

Ah yes, that is the case:

ember-table/addon-test-support/pages/ember-table.js

Lines 74 to 77 in 8519064

	async selectRange(beginIndex, endIndex) {
	await this.body.rows.objectAt(beginIndex).click();
	await this.body.rows.objectAt(endIndex).clickWith({ shiftKey: true });
	},

the test always uses a click as the starting input, then the second click is shift+click.

I think that means we have essentially left undefined what the behavior for shift+click when there is nothing selected should be.

Some existing UX to consider:

• In the MacOS finder shift+click when nothing is selected actually selects from item Initial cleanup of gh-pages #1 to the clicked item.
• In a <select multiple> shift+click with nothing selected simply acts like a click.
• In a browser selecting text on a webpage shift+click with nothing selected acts like a click.
• In Google Sheets shift+click with nothing selected effectively select from the first item (the top-left cell) to the cell clicked.

Are there other cases to consider? We just need to make a design decision, I will raise it with some other maintainers as well.

[mixonic]

IMO selectRange should stay as-is, and we should add tests for this specific case.

[frykten]

@mixonic I don't see any other cases.
Could be interesting to chat about it, right. Gotta admit, we're more into shift+click with nothing selected simply acts like a click, here, but the other design is a good idea also.

I fixed-up the PR to add the test.

[mixonic]

@frykten ok today I got to sync up with @bantic and @twokul and we think having a shift+click without any existing selection work as a click is fine. I think this PR already reflects that 👍

@bantic looked at the CI quickly and it seems a point revision of prettier is causing the build to fail :-/

[mixonic]

CI on master fixed as of #790, @frykten can you rebase this?

[frykten]

Done @mixonic

[mixonic]

Great! Thank you @frykten I'm not sure we will make a release for a week or two because of the holiday, but keep an eye out.