Add JavaScript dateFormat & numberFormat function

[JSteunou]

Is your feature request related to a problem? Please describe.

For a usage outside of react, in javascript i18n contains t, plural, select, selectOrdinal but no dateFormat nor numberFormat helpers like react components.

Using date from core works, but it requires to create a function with current language before being able to use it. If you don't have the need for cached formatter this is tedious.

This is just sugar, but nice sugar :)

Describe the solution you'd like

i18n.dateFormat('2018-08-29', {weekday: 'long', year: 'numeric', month: 'long', day: 'numeric'})

Describe alternatives you've considered

import {date} from '@lingui/core'

date(i18n.language, {weekday: 'long', year: 'numeric', month: 'long', day: 'numeric'})('2018-08-29')

[tricoder42]

Sounds good! I don't know why it's not included already.

Interested in sending PR?

[JSteunou]

I would but I have very limited bandwidth so do not wait for me :(

[JSteunou]

👍 🍺

[tricoder42]

Released in v2.7.0.

[JSteunou]

Thank you a ton @tricoder42 !