Expose "selectTab" method for programmatic selection

[thetutlage]

This PR moves the selectTab method on the TabContainer class. Doing so will enable programmatic select of tabs by calling this method. The proposal was shared in this issue #55

Changes

• The selectTab method no longer accepts the tabContainer instance. It uses this implicitly.
• A conditional has been added to check for out of bounds index (since the method is public now). Right now, I am silently returning when the index > no of tabs. Maybe we can raise an exception here? Just wanted feedback on how to proceed with that.

Lemme know if something needs attention. Happy to improve the PR :)

[keithamus]

I think throwing a RangeError here would be very useful.

[keithamus]

Looks great so far! Throwing would be helpful, and adding tests for out-of-bounds would be 😲 🎉

[keithamus]

Perhaps a more succinct error message here:

Suggested change

	throw new Error(`Cannot select tab at index "${index}" as it exceeds the total number of tabs`)
	throw new RangeError(`Index "${index}" out of bounds`)

[thetutlage]

Sure :)

[koddsson]

This looks fine to me. I've got slight worries that this might regress the experience for screenreader users, but I couldn't find anything about if we should announce when the tab changes to users.

[thetutlage]

Not an accessibility expert at all. But, shouldn't setting aria-selected and tab-index will take care of it?

My use case is to have a language switch on the website and once you select language (ie TypeScript or JavaScript), all the codeblocks on that page will switch to the selected language.

tabs-switch.mov

[thetutlage]

Any feedback guys?

[keithamus]

Thanks for your patience @thetutlage, this slipped between the cracks of our first responder rotation. @dgreif would you kindly give this some extra 👀 and if you're happy merge+release?

[thetutlage]

Thanks :)