Select2 allowClear not working with dynamic dropdown list

Question

I have tried a lot of ways to fix this problem.

At a dynamic list loaded via ajax, I can't make allowClear work.

Here is my jsFiddle

HTML:

<select id="first" class="init-select2" data-placeholder="First dropdown" data-allowclear="true">
    <option></option>
    <option>First option</option>
    <option>Second option</option>
</select>
<select id="second" class="init-select2" data-placeholder="Second Dropdown" data-allowclear="true" disabled="disabled">
    <option></option>
</select>

Javascript:

$(function() {
    $('.init-select2').removeClass('init-select2').each(function(){
            if ($(this).attr("data-allowclear") && $(this).attr("data-allowclear") == "true"){
                $(this).select2({
                    allowClear: true
                });
            } else if ($(this).attr("data-allowclear") && $(this).attr("data-allowclear") == "false") {
                $(this).select2({
                    allowClear: false
                });
            }
        });

    $('#first').change(function () {
        var options = [];
        $.ajax({
            type: "POST",
            url: "/echo/json/",
            data: {"json":JSON.stringify({"one":"first","two":"second","three":"third"})},
            cache: false,

            success: function(data) {
                $.each(data, function (index, value) {
                    options.push("<option>" + value + "</option>");
                    $("#second").find('option').remove().end().append(options).attr("disabled", false).select2({ allowClear: true });
                });
            }
        }); 
    });
});

in jsfiddle are already added the select2 javascript and css, please have a look there

Answer 1

Fixed by adding an "<option></option>" to second dropdown each time I change the value of first dropdown. See success handler below:

$('#first').change(function () {
    var options = [];
    $.ajax({
        type: "POST",
        url: "/echo/json/",
        data: {
            "json": JSON.stringify({
                "one": "first",
                "two": "second",
                "three": "third"
            })
        },
        cache: false,

        success: function (data) {
            options.push("<option></option>");
            $.each(data, function (index, value) { 
                options.push("<option>" + value + "</option>");
                $("#second").find('option').remove().end().append(options).attr("disabled", false).select2({
                    allowClear: true
                });
            });
        }
    });
});

Answer 2

Example of one of my own, as you can see I don't use "option" tags within my loop.

            function companyURL() {
                if ($.isNumeric($('#supplier_select').val())) {
                    return company_url + '/' + $('#supplier_select').val() + '/';
                } else {
                    return company_url;
                }
            }

            var results = [];

            $('.company_select').select2({
                ajax: {
                    url: function () {
                        return companyURL();
                    },
                    dataType: 'json',
                    quietMillis: 100,
                    data: function (term) {
                        return {
                            term: term
                        };
                    },
                    results: function (data) {
                        results = [];
                        results.push({
                            id: '',
                            text: 'Select a company'
                        });
                        $.each(data, function (index, item) {
                            results.push({
                                id: item.company_id,
                                text: item.company_name
                            });
                        });
                        return {
                            results: results
                        };
                    }
                }
            });