feat(pagination): Added aria label input for accessibility

[thbt]

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• read and followed the CONTRIBUTING.md guide.
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• added/updated any applicable tests.
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• added/updated any applicable demos.

[maxokorokov]

Hey. Two things:

1. I would not add ariaLabel on ALL demos, maybe only one like pagination-config or a proper accessibility demo. They are supposed to be simple and to the point.

2. Maybe I'm talking nonsense, but can't we simply stick [attr.aria-label] on the host element by the way, not on the inner <nav>. They won't read it properly?

[maxokorokov]

no need in :string type

[thbt]

Thanks for the review!

1. Makes sense, I removed it from all demo except config.
2. It might not change a lot for the screen readers, but we wouldn't be in line with bootstrap markup anymore if we applied the attribute on the host instead of the inner <nav>.

(Don't know why the travis build is failing though 🙁 ...)

[pkozlowski-opensource]

Maybe I'm talking nonsense, but can't we simply stick [attr.aria-label] on the host element by the way, not on the inner

. They won't read it properly?

@maxokorokov has a point and tbh I would go even a step further - if we would to simply forward a proerty binding to an attribute on a host... why do we need to do things at all? I mean, why not show people to simply use <ngb-pagination aria-label="...">?

Could we test it with screen readers and check of we need to do anything here at all?

[pkozlowski-opensource]

I've just checked with ChromeVox and it seems like sticking aria-label on <ngb-pagination> has no effect... So we need to introduce a new input. Was just wondering if we can have it as aria-label instead of ariaLabel (probably not, but worth trying)?

Other thing: this PR doesn't add <span class="sr-only">(current)</span></a> for an active item as done in http://v4-alpha.getbootstrap.com/components/pagination/#disabled-and-active-states - should be added as part of the accessibility work for pagination.

[pkozlowski-opensource]

@thbt could you please add support for the <span class="sr-only">(current)</span> to this PR as commented above? Ref: http://v4-alpha.getbootstrap.com/components/pagination/#disabled-and-active-states

You might also find this article useful: http://www.a11ymatters.com/pattern/pagination/

[pkozlowski-opensource]

LGTM. Let's wait for the TravisCI build and if it is green I'm going to merge this one. Thnx!