Getting errors (already defined variable in if statement)

Question

I am getting errors in JSlint and JSFiddle, however the scripts works perfectly.

I want to fix the errors, but I don't really know what to do.

The error I am getting is: 'allmonth is already defined'

The javascript (it's just a part of a full script, but here's the part with the errors)

$.each(data.product.variants, function (index, variant) {
     var oldvartitle2 = variant.title,
         oldvartitle = oldvartitle2.substring(oldvartitle2.indexOf(":") + 1),
         newvartitle = oldvartitle.substr(3),
         splitted = newvartitle.split(' '),
         month2 = splitted[1];
     if (month2 === 'januari') {
         var allmonth = '01';

     }
     if (month2 === 'februari') {
         var allmonth = '02';

     }
     if (month2 === 'maart') {
         var allmonth = '03';

     }
     if (month2 === 'april') {
         var allmonth = '04';

     }
     if (month2 === 'mei') {
         var allmonth = '05';

     }
     if (month2 === 'juni') {
         var allmonth = '06';

     }
     if (month2 === 'juli') {
         var allmonth = '07';

     }
     if (month2 === 'augustus') {
         var allmonth = '08';

     }
     if (month2 === 'september') {
         var allmonth = '09';

     }
     if (month2 === 'oktober') {
         var allmonth = '10';

     }
     if (month2 === 'november') {
         var allmonth = '11';

     }
     if (month2 === 'december') {
         var allmonth = '12';

     }
     var allmonths = splitted[0] + '/' + allmonth + '/' + splitted[2];
     $('.multiple_' + index2 + '_variants .datacursusul_' + index2 + '_ul').append('<li class="' + allmonths + '">' + oldvartitle + '</li>');
 });

I want to change the 'allmonth' variable to a number depending on what the month2 variable contains.

Thanks!

Answer 1

You must declare all memory at the beginning of your code blocks to be jslint compliant. So var allmonth; should be part of the var at the very beginning. Like so

 var oldvartitle2 = variant.title,
     oldvartitle = oldvartitle2.substring(oldvartitle2.indexOf(":") + 1),
     newvartitle = oldvartitle.substr(3),
     splitted = newvartitle.split(' '),
     month2 = splitted[1],
     allmonth;

You must also remove the var from the other allmonth variables.

Similarly with allmonths.

Answer 2

 var allmonth = '';
 if (month2 === 'januari') {
          allmonth = '01';

 }

Answer 3

There are much more concise ways to do something like that. One is to replace that series of "if" statements with a "switch" statement. But the way I would do it is like so:

var month_names = ['januari', 'februari', 'maart', 'april', 'mei', 'juni', 'juli', 'augustus', 'september', 'oktober', 'november', 'december'];
var month_index = month_names.indexOf(month2) + 1;
var allmonth = ("0" + month_index).substr(-2);

Note that if no match is found, allmonth will be "00".

(Edited to return a two-digit string with zero padding.)

Answer 4

As stated above it's probably undeclared allmonth. You could however sligthly refactor your code:

var data = {
    product: {
        variants: ['maart']
    }
}

$.each(data.product.variants, function (index, variant) {
    function pad(number) {
        return number < 10 ? '0' + number : number;
    } 
    var month2 = variant,
    months_order = ['januari', 'februari', 'maart', 'etc'],
    allmonth = pad(months_order.indexOf(month2) + 1);
    console.log(allmonth); // 03

});

Fiddle

Answer 5

You could use an array to store the month names and then just use indexOf to get the index and pad it out with a zero where applicable.

var monthList = ['januari', 'februari', 'maart', 'april', 'mei', 'juni', 'juli', 'augustus', 'september', 'oktober', 'november', 'december'];

var month2 = 'maart';

function getMonth(month) {
  var num = monthList.indexOf(month) + 1;
  if (num === 0) return null;
  return num.toString().length === 1 ? '0' + num : num;
}

console.log(getMonth(month2)); // 03

Demo