How to get the locale format?

What is the equivalent of this moment code?

moment.localeData().longDateFormat('L')

[iamkun]

Added in #734, and will be available in the next release.

Usage:

var dayjs = require("dayjs")
var LocalizedFormat = require( 'dayjs/plugin/localizedFormat')
var localeData = require( 'dayjs/plugin/localeData')

dayjs.extend(LocalizedFormat)
dayjs.extend(localeData)

console.log(dayjs().localeData().longDateFormat('L'))

[xrzhuang]

how do I test that this works? I want to observe localeData() on various different formats. For example it appears to work on my browser, but I want to view the result for other locales like de