Case conversion with specific locale

[vozzen]

Case conversion are done with String.prototype.toLocaleLowerCase() and String.prototype.toLocaleUpperCase() without explicit locale parameter and this causes host dependent output.
Example:

camelCase('lorem-ipsum')
//=> 'loremIpsum' if host locale is en-US
//=> 'loremİpsum' if host locale is tr-TR

This causes unexpected results int hosts with non en-US environment.

I'd suggest to extend options parameter to have a locale property to be passed to aforementioned methods.

camelCase('lorem-ipsum', {locale: 'en-US'});
//=> 'loremIpsum' if host locale is en-US
//=> 'loremIpsum' if host locale is tr-TR

[selimrecep]

I am experiencing same issue too. Just because of this error, I couldn't get Jest work without workarounds.

i => İ
ı => I
(Lower => Upper s in Turkish)

[selimrecep]

I have created PR. I think that will fix it.

[vozzen]

@selimrecep Sorry, in parallel I've also submitted a PR. Any of them is fine :)