How to get the weekday names using Intl?

Question

I'd like to display in my i18n-ed app a list of the 7 weekdays:

Sunday, Monday, Tuesday... Saturday

I rely on the Intl global object for formatting date/time but I can't find an easy way to get only the weekday names.

I thought I could add some days to the EPOCH time, to reach the first day of the week, but I'm failing to find a formatter printing just the weekday.

var date = new Date(0);
date.setDate(4 + day);
for (var i = 0; i < 7; i++) {
  var weekday = new Intl.DateTimeFormat(["en"], {
      weekday: "short" // ?? what should I put here
  }).format(date);
  console.log(weekday);
}

Output:

Sunday, January 4, 1970
Monday, January 5, 1970
Tuesday, January 6, 1970
Wednesday, January 7, 1970
Thursday, January 8, 1970
Friday, January 9, 1970
Saturday, January 10, 1970

Desired output:

Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday

I also would like to have a shorter version of the days, such as Sun, Mon, Tue....

Alternatively, is there a way to get the weekday strings from Intl? I tried to explore the object via console but I couldn't find them.

Answer 1

I was misled because I was using the Intl polyfill, which does not support yet { weekday: "short" } as option.

Using native Intl implementations works as expected.

Answer 2

my solution in 2021 with es6

/**
 * Return list of days
 * 🌍 localeName : name of local, f.e. en-GB, default es-MX
 *  ✅ weekday   : formart of weekday short/long (Default)
 */
function daysForLocale(localeName = 'es-MX', weekday = 'long') {
  const format = new Intl.DateTimeFormat(localeName, { weekday }).format;
  return [...Array(7).keys()]
    .map((day) => format(new Date(Date.UTC(2021, 5, day))));
}

// ##############################################################
// testing daysForLocale function
// ##############################################################
console.log(daysForLocale());
// ['domingo','lunes',...,'viernes','sábado']
console.log(daysForLocale('en-GB', 'short'));
// ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri','Sat']
console.log(daysForLocale('ja-JP', 'short'));
// ['日', '月', '火','水', '木', '金','土']