Tabs: Fix issue where selecting a tab in a set with no active tab errors out

[austinoneil]

Description

Fix issue where selecting a tab in a set with no active tab errors out.

References #2197

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

Added E2E test, manually tested using provided HTML (thank you, reporter)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

[netlify]

✅ Deploy Preview for moduswebcomponents ready!

Built without sensitive environment variables

Name	Link
🔨 Latest commit	137c3ea
🔍 Latest deploy log	https://app.netlify.com/sites/moduswebcomponents/deploys/660c80013f11c8000894644d
😎 Deploy Preview	https://deploy-preview-2383--moduswebcomponents.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
Lighthouse	1 paths audited Performance: 28 (🟢 up 2 from production) Accessibility: 98 (no change from production) Best Practices: 92 (no change from production) SEO: 92 (no change from production) PWA: - View the detailed breakdown and full score reports

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[cjwinsor]

@austinoneil This can be simplified a bit further with

if (activeTab?.id != null) {
    return;
}

We can leverage optional chaining and != null for nullish coalescing. If you can make this small change I will go ahead and merge afterwards.

[austinoneil]

This change was fixing an issue with an if statement that appeared to avoid emitting if the active tab was clicked. This change breaks some tests. That said, it looks like my change breaks some functionality. I'll fix it and add a test and push.

[austinoneil]

Done, though adding a test proved to be difficult (it uses spyOn for event emitters, which seems to be causing test issues in main with other tests as well)

[cjwinsor]

@austinoneil Can you go more into detail about what you mean by "seems to be causing test issues in main"?

[austinoneil]

@cjwinsor When I run npm run test locally on main, I get the failures for the following tests:

• modus-select emits "valueChange" event
• modus-table Display items per page list when pageSizeList is enabled

Both are related to using the spyOn method and both are failing on my machine on main. I do not know whether this is an issue with my setup or if it's failing across the board. I am running nvm use 18.17.0 when opening my IDE.

[cjwinsor]

@austinoneil Very peculiar, I switched to 18.17.0 and ran tests against main without issue on my windows laptop. I'm going to keep my eye on this and get I get a chance try to run within a sandbox and wsl.