Why is date-fns example code not working with Vue?

Question

JavaScript

I took the example directly from the main page, but it does not work in
Computed

import { format, formatDistance, formatRelative, subDays } from 'date-fns'
formatDistance(subDays(new Date(), 3), new Date())

I have in Computed

import { formatDistance, subDays } from 'date-fns'

formattedValue () {
      return formatDistance(subDays(new Date(), 3), new Date())
    }

MistakeObject(...) is not a function