javascript - Intl.DateTimeFormat shows time being 24:59

Question

Hey everyone| just checking if I am doing something wrong. The code below gives me time = 24:59, in Prague (GMT+1). Using Chrome.

new Intl.DateTimeFormat(
  'en',
  {
     weekday: 'long',
     month: 'long',
     day: 'numeric',
     hour: 'numeric',
     minute: 'numeric',
     hour12: false
  }
 ).format(new Date('2020-03-11T23:59:00Z')
) 
// "Thursday, March 12, 24:59"

When using the .getHours() I will get a correct value of 0 though.

new Date('2020-03-11T23:59:00Z'); // Thu Mar 12 2020 00:59:00 GMT+0100 (Central European Standard Time)
new Date('2020-03-11T23:59:00Z').getHours(); // 0

Thanks for suggestions, I didn't found any related issues about this.

Tomas

Answer 1

Your code gives me "Thursday, March 12, 00:59" in Firefox and "Thursday, March 12, 24:59" in Chrome (80.0.3987.149)

There appears to be a bug open for Chrome 80 https://support.google.com/chrome/thread/29828561?hl=en, open since February, but not much is said about whether it will be fixed and how. Consider upvoting it.

According to a comment posted there, you could work around the issue by replacing the hour12 property with hourCycle: 'h23'.

new Intl.DateTimeFormat(
  'en',
  {
     weekday: 'long',
     month: 'long',
     day: 'numeric',
     hour: 'numeric',
     minute: 'numeric',
     hourCycle: 'h23'
  }
 ).format(new Date('2020-03-11T23:59:00Z')
)
// "Thursday, March 12, 00:59"

This seems to do the trick for me