startOf('week') is not respecting locale setting

While most countries in the world assume the week starts on Monday, US, Canada, and Australia consider Sunday as the first day of the week. It seems that luxon hard-coded the start of week as Monday.

// prints "2018-11-19T00:00:00.000-08:00"
console.log(DateTime.fromISO('2018-11-22T10:00', {zone: 'America/Los_Angeles'}.startOf('week').toISO());

Note that moment does actually respect the locale setting

// prints "2018-11-18T08:00:00.000Z"
console.log(moment.tz('2018-11-22T10:00', "America/Los_Angeles").startOf('week').toISOString());

[lostdesign]

While this is a quite old issue, I still wanted to share my quick work around:

const date = DateTime.fromISO('2021-09-16').startOf('week')
const sunday = date.minus({day: 1})

By simply subtracting a day, you get a sunday which you can use as a start point for further actions.

edit: However, once possible, this should be part of the API.

[dasa]

As far as I know, there’s no Intl API I can use to get the local first day of the week.

It’s coming soon: https://chromestatus.com/feature/5566859262820352