Fix <LinkTo> usage with class attribute.

[Alonski]

Using a helper in a class property doesn't render the class in the rendered HTML.

Example:

<LinkTo @route="foo" class={{concat "main"}}>Link</LinkTo>

Expected HTML:

<a href="/foo" class="main ember-view">Link</a>

Actual:

<a href="/foo" class="ember-view">Link</a>

Fixes: #83

[simonihmig]

@Alonski It seems you are running into the same linter issue as me a few times: CI runs with the latest dependencies, where prettier rules are slightly different, so what's passing locally is failing in CI. You would have to yarn --no-lockfile and yarn lint:js --fix locally to fix the linting error that is failing the build in CI!

I just created #84 to fix this...

[simonihmig]

Thanks @Alonski for working on this! I said yesterday that I would try to fix it today, but you seem to already have found the problem, so I'll leave it up to you to finish the PR, unless you want me help! :)

[simonihmig]

You are not passing hash here. But yes, this is the culprit, my initial implementation was too naive.

Also I realized the original generic transform for angle brackets also has to deal with transforming attributes obviously, and has this figured out properly already: https://github.com/rwjblue/ember-angle-bracket-invocation-polyfill/blob/master/lib/ast-transform.js#L40-L53.

So I think it would be best to extract this into another helper function, and reuse it across all three transforms (including the one for <Input>, which suffers from the same problem I think).

[Alonski]

@simonihmig Ready 4 Review :) Thanks!

[rwjblue]

Looks good! Can you:

• rebase and run eslint fix (I think that will fix some of the issues with formatting in CI)
• add another test for <LinkTo @route=“bar” class=“ma{{“in”}}”></LinkTo> (to confirm that ConcatStatements are handled right)

Thank you!