[providers/storyblok] Storyblok focal point filter trips up splitfilters()

[grgcnnr]

Focal point doc: https://www.storyblok.com/docs/api/image-service/operations/focal-point

Splitfilters fn: https://github.com/ascorbic/unpic/blob/main/src/providers/storyblok.ts#L31

The storyblok image CDN expects a focalpoint filter to be set like this /m/500x300/filters:focal(1869x1674:1870x1675)
but splitfilters() expects colons to be reserved for seperating filters so it gets confused.

the lightest touch solution to this is to URIEncode the focal filter before splitting.

focal = encodeURIComponent(focal)

Happy to PR somethign if that's helpful

[ascorbic]

Thanks! That would be great if you could

[grgcnnr]

#171