defaultLocale in the bundle

[diogen737]

First off - thanks for a great lib!

I need some clarification here.
Let's say I know what locale I'll be using throughout the app at the build time, so I do this:

import { setDefaultOptions } from 'date-fns';
import { de } from 'date-fns/locale';

setDefaultOptions({ locale: de });

Yet the en-US end up in the bundle anyway.

Is there a way to tell date-fns/bundler to truly set one default locale once and for all?

[fturmel]

en-US is the only hard-coded locale in the library itself, so it's always going to be included by default. It shouldn't matter much for most people since it's only about 5.5 Kb gzipped.

date-fns/src/_lib/defaultLocale/index.ts

Line 1 in fadbd4e

import defaultLocale from '../../locale/en-US/index'

There is official documentation to exclude locales with Webpack's ContextReplacementPlugin. I don't think the approach will allow you to strip out en-US though.

There might be other (better?) ways, but I did successfully manage to use the string-replace-loader Webpack loader to change the default locale to de with the following rule:

{
  test: /_lib\/defaultLocale\/index\.js$/,
  loader: 'string-replace-loader',
    options: {
      search: '/locale/en-US/',
      replace: '/locale/de/',
    },
}

You won't need to explicitly set de as the default locale anymore either:

import { format } from 'date-fns';

format(new Date(), 'PPPP') // Sonntag, 30. Oktober 2022