JavaScript: Month name to Number and Month number to month name

month-name-number-conversion.js

var months = [
    'January', 'February', 'March', 'April', 'May',
    'June', 'July', 'August', 'September',
    'October', 'November', 'December'
    ];

function monthNumToName(monthnum) {
    return months[monthnum - 1] || '';
}
function monthNameToNum(monthname) {
    var month = months.indexOf(monthname);
    return month ? month + 1 : 0;
}

if (monthNumToName(12) == 'December') alert('12 == December!')
if (monthNameToNum('June') == 6) alert('June == 6!')

This has a bug. If you pass in January, you get 0 back instead of 1..
Should be
return month != -1 ? month + 1 : undefined

This has a bug. If you pass in January, you get 0 back instead of 1..
Should be
return month != -1 ? month + 1 : undefined

If you plan to use this with js Date function you will want the 'Jan' date to be 0.

If you plan to use this with js Date function you will want the 'Jan' date to be 0.

and then Feb 2 ???

`const moment = require('moment');
moment.locale('en'); // sets words language (optional if current locale is to be used)
let months = moment.months() // returns a list of months in the current locale (January, February, etc.)
// console.log(months);
var months_obj = {};

for (let month_num_key in months) {
months_obj[parseInt(month_num_key) + 1] = months[month_num_key];
}

console.log(months_obj);`