I have very simple problem, but couldn't find good simple DRY solution. I want to convert number of hours to HH:MM format. My try with Moment.js is:

var hours = 10.5
var hour_string = moment(hours*3600*1000).format('HH:MM')

But unfortunately I get:

"11:01"

and have no idea why. Of course my wanted result is "10:30".

I'd like just do it in the easiest way, similar as I can do in Rails:

Time.at(hours*3600).utc.strftime("%H:%M")

Any ideas?

I have very simple problem, but couldn't find good simple DRY solution. I want to convert number of hours to HH:MM format. My try with Moment.js is:

var hours = 10.5
var hour_string = moment(hours*3600*1000).format('HH:MM')

But unfortunately I get:

"11:01"

and have no idea why. Of course my wanted result is "10:30".

I'd like just do it in the easiest way, similar as I can do in Rails:

Time.at(hours*3600).utc.strftime("%H:%M")

Any ideas?

• javascript
• momentjs

2 Answers 2

Okay, I found the reason. "MM" means months, not minutes, which are "mm". And the hour shift was caused by timezones, which we can omit using the utc function. The final solution is:

moment.utc(hours*3600*1000).format('HH:mm')

let hour = 10;
let minute = 30;

moment({ hour, minute }).format('HH:mm');

// output: 10:30