How to remove extra commas from a list

I have a list of checkboxes and if one is checked, I'm appending the checkbox value to a input field elsewhere on the page. If a checkbox is unchecked, I'm removing the value from the hidden input field. What is happening is if the values are being added and removed just fine but they are leaving a series of commas behind when a check box is checked, unchecked, checked, unchecked, etc.

A) should I worry about it B) if yes, how should I alter my add/append routine (see below) or is there a better way to do what I'm doing? I'd prefer to end up with a clean list like 0_1,0_2,41_4 opposed to 0_1,,,,,,,,,,,,,,,,0_2,,,,41_4,,,,.

    <input type="text" value="0_1,0_2,41_4" id="EOStatus_SelLayers" />

    // example of dataset:  '0_1,0_2,41_4'; 
    if ( xyz.hasClass("icon-check-empty") ) {
        var existing_str = $('#EOStatus_SelLayers').val();
            if (existing_str==null || existing_str==""){
                //add
                $('#EOStatus_SelLayers').val(id);
            }
            else {
                //append    
                $('#EOStatus_SelLayers').val( existing_str + ',' + id);                 
            }
    }
    else {
        $(xyz).removeClass("icon-check").addClass("icon-check-empty");
        var old_str = $('#EOStatus_SelLayers').val();
        var new_str = old_str.replace(','+id,'');
        var new_str = old_str.replace(id,'');
        $('#EOStatus_SelLayers').val(new_str);
    }

In the else statement, I could do something like this:

var new_str = old_str.replace(id,'');  
var new_str = old_str.replace(',,',',');

Answers


You can replace the id with an empty string and then replace any extraneous commas.

There are three places you can end up with an extraneous comma:

  1. A double comma somewhere in the middle (needs to be replaced with a single comma)
  2. A leading comma (needs to be removed)
  3. A trailing comma (needs to be removed)

You can address all three cases with these two replace operations:

.replace(/,,/g, ",").replace(/^,|,$/g, "");

Which in place could look like this:

else {
    $(xyz).removeClass("icon-check").addClass("icon-check-empty");
    var old_str = $('#EOStatus_SelLayers').val();
    var new_str = old_str.replace(id,'').replace(/,,/g, ",").replace(/^,|,$/g, "");
    $('#EOStatus_SelLayers').val(new_str);
}

If you're using jQuery - a simpler approach would be simple re-set the input value each time a change was made to checkboxes? Simply concat the ID of each :checked input... If you're using a custom lib to change the appearance of the checkboxes I'm sure there's on-change event triggers that would allow the following to work.

Alternatively you should be able to edit to suit your specific needs.

$('input[type=checkbox]').on('change', function(e) {
    var newVal = [];

    $('input[type=checkbox]:checked').each(function() {
        newVal.push($(this).attr('id'));
    });

    $('#EOStatus_SelLayers').val(newVal.join(','));
});

Or, in the case you're using images:

$('[class^="icon-check"]').on('click', function(e) {
    var newVal = [];

    $('.icon-check').each(function() {
        newVal.push($(this).attr('id'));
    });

    $(this).toggleClass('icon-check-empty');
    $(this).toggleClass('icon-check');

    $('#EOStatus_SelLayers').val(newVal.join(','));
});

Disclaimer: not tested - but looks like it should work.


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