ensure map areas have non-empty alts

[Chovin]

closes #223

[msftclas]

All CLA requirements met.

[Chovin]

hmm, if this is is typescript, the only time i’d be able to tell if the area element is in a map element is if they’re both there together in their “literal” form right?

[JoshuaKGoldberg]

if they're both there together in their "literal" form

Sorry @Chovin I don't follow. Do you mean that the only way to tell is if the literals are together, like this?

<map ...>
    <area ... />
</map>

...rather than:

<SomeComponentThatReturnsAMap>
    <area ... />
</SomeComponentThatReturnsAMap>

If that's the case, then yes - there isn't a (known?) good way to validate what JSX elements are returned by a method.

[JoshuaKGoldberg]

Looks like you have a build failure:

src/reactA11yImgHasAltRule.ts(87,51): error TS2339: Property 'parentNode' does not exist on type 'JsxOpeningLikeElement'.
  Property 'parentNode' does not exist on type 'JsxSelfClosingElement'.

Are you missing a cast somewhere, or is that meant to be node.parent?

https://ci.appveyor.com/project/HamletDRC/tslint-microsoft-contrib/builds/19493473/job/jxjskojh6r8pqd5j

[Chovin]

@JoshuaKGoldberg ah I see. I'm assuming that's the best we can do here and just ignore cases like this?

<SomeComponentThatReturnsAMap>
    <area ... />
</SomeComponentThatReturnsAMap>

[Chovin]

hmm. parent.type === 'map' ?
Sorry, this is my first time touching React 🙃

[JoshuaKGoldberg]

This looks like it should work, super. Let's add some tests to ReactA11yImgHasAltRuleTests.

[Chovin]

Awesome! I’ll get to that test soon. Thanks!

[JoshuaKGoldberg]

Ping @Chovin, are you still available to finish up this PR? Looks like it'd be a good one to have in.

[Chovin]

I’d like to get back to this but will have to do so in a few weeks. Thanks for following up @JoshuaKGoldberg !

[JoshuaKGoldberg]

Closing now to keep the queue small so others feel welcome to take this on themselves. Feel free to ping me if you'd like to pick this back up @Chovin!