feat(core): support styles and styleUrl as strings

[crisbeto]

Adds support for passing in @Component.styles as a string. Also introduces a new styleUrl property on @Component for providing a single stylesheet. This is more convenient for the most common case where a component only has one stylesheet associated with it.

[eneajaho]

Hello @crisbeto

This example below looks like it accepts multiple urls because of the naming.
styleUrls: 'dir/styles.css, dir/styles1.css'

Imo, The correct way it should look like is:
styleUrl: 'dir/styles.css'

But that would require big changes I believe.

[crisbeto]

Yeah, I agree that the naming is problematic, but I think that splitting it on the comma would be weird as well. Introducing a styleUrl property won't be that much more work to support, but it increases the API surface. WDYT @jelbourn?

[jnizet]

My two cents here: the Angular API already has at least one other place where it uses the plural form to also accept a single thing: https://angular.io/api/forms/AbstractControlOptions. So keeping styleUrls would at least be consistent.

[crisbeto]

Based on what we discussed with @jelbourn: I've introduced a new styleUrl property and kept styleUrls as a string[].

[pkozlowski-opensource]

LGTM

Reviewed-for: public-api
Reviewed-for: fw-core

[jessicajaniuk]

reviewed-for: fw-core, fw-testing, public-api

[AndrewKushnir]

This PR was merged into the repository by commit 59387ee.

[spock123]

Thank you guys, I know this is a silly small thing but it's really something I bet all developers have come across: it really makes the developing experience better, because 99% of all cases there'll only be 1 styles file. Thanks!!!

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}