formatNumber() ignores current language convention while formatting numbers

[rob006]

Polish language uses space as thousands separator, so 100000 should be formatted as 100 000. But it looks like formatNumber() has really simple implementation with hardcoded comma as separator:

https://github.com/flarum/core/blob/d4e3254395fa03a0653218a543e23ad9de76ae77/js/src/common/utils/formatNumber.ts#L9-L11

It may be a good idea to switch to something like Intl.NumberFormat or toLocaleString() instead - both new Intl.NumberFormat('pl').format(number) and number.toLocaleString('pl') returns correct format.

[wolfgang-demeter]

I second that! In Germany it should read 100.000, and not 100,000.

[askvortsov1]

If this is already included in browsers, the fix should be quite easy and shouldn't have a bundle size cost.