How to get the meridian (am / pm) with momentsjs and angularjs

Question

I would like could help me, I have a question to the library moments.js, I have an application in angularjs where I have six select, for the year, for the month, for day, for the hour, for minutes and one for the am / pm format, use the following format moment to build m.format date ('YYYY-MM-DD hh: mm: ss a),
the code is as follows:

var m = moment([scope.val.year, scope.val.month, scope.val.date, scope.val.hour, scope.val.minute]); //build date 



model.$setViewValue(m.format('YYYY-MM-DD hh:mm:ss a'))

I get the data

m.hour ()

,

m.minute ()

, etc but there is a way to get the am / pm format, I have not found anything about it, something perhaps as

m.meridian () => "am "or" pm "

.

I would build the array passing as parameter if am or pm, and then also would get from any date if am or pm date.

Thanks for any help given.

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Answer 1

A few things:

The word you're looking for is "meridiem", not "meridian". It's a Latin word meaning "mid-day". A.M. is "ante meridiem" (before mid-day) and P.M. is "post meridiem" (after mid-day).
The .hours() function and the input array passed to the moment constructor both expect hours of a 24-hour clock, from 0 to 23. There is no built-in function to accept or output a 12-hour clock value, or a meridiem (am/pm).
The parsing and formatting functions in moment do have options for 12-hour clock hours (h or hh) and meridiem (A or a), but you're not parsing or formatting in your use case, so they would be a bit clumsy to use. In particular, they are based on moment's current locale settings, so testing a string would be problematic if the locale wasn't fixed to a specific language.

You can use these simple functions to convert from 12-hour + meridiem to 24-hour and vice-versa. They are not specific to moment, so you can also use them with the Date object or elsewhere.

function hours12to24(h, pm) {
    return h == 12 ? pm ? 12 : 0 : pm ? h + 12 : h;
}

function hours24to12(h) {
    return {
        hour : (h + 11) % 12 + 1,
        pm : h >= 12
    }
}

To test these functions:

function test() {
  for (var i = 0; i <= 23; i++) {
    var x = hours24to12(i);
    var h = hours12to24(x.hour, x.pm);
    console.log(i + " == " + x.hour + (x.pm ? " pm" : " am") + " == " + h);
  }
}

Also, be careful when calling .month() to get the month number, the results are 0-11, not 1-12. The same is true when building the input array. Your dropdown either needs to use 0-11, or you need to add or subtract 1 accordingly.

How to get the meridian (am / pm) with momentsjs and angularjs

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