Selectize clear button

selectize-clear_button.js

/**
 * Plugin: "clear_button" (selectize.js)
 * Copyright (c) 2015  Dmitri Piatkov & contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this
 * file except in compliance with the License. You may obtain a copy of the License at:
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under
 * the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
 * ANY KIND, either express or implied. See the License for the specific language
 * governing permissions and limitations under the License.
 *
 * @author Dmitri Piatkov <dkrnl@yandex.ru>
 */
 
Selectize.define("clear_button", function(options) {
    var self = this;
    if (self.settings.mode === "multiple") {
        return;
    }

    options = $.extend({
        label     : "<i class=\"fa fa-times\"></i>",
        className : "btn btn-block btn-link",
        append    : true
    }, options);

    self.on("initialize", function() {
        self.$clear_button = $("<button type=\"button\" tabindex=\"-1\"></button>");
        self.$clear_button.addClass(options.className).html(options.label);
        self.$clear_button.prop("disabled", !self.items.length);
        self.$dropdown.prepend(self.$clear_button);
        self.$clear_button.click(function() {
            if (self.items.length) {
                self.setValue("");
                self.onChange();
                self.close();
            }
        });
        self.on("change", function() {
            self.$clear_button.prop("disabled", !self.items.length);
        });
    });
});

Usage example:

$("select.form-control").each(function() {
        var select = $(this), options = {plugins: {}};
        if (select.prop("multiple")) {
            options.hideSelected = false;
            options.plugins["remove_button"] = {}; // default selectize pluging
            options.plugins["optgroup_checkbox"] = {}; // https://gist.github.com/dkrnl/c97099bd042d8180426b
        } else {
            options.plugins["clear_button"] = {}; // this plugin
        }
        options.allowEmptyOption = true;
        options = $.extend(true, {}, options, select.data());
        select.selectize(options);
 });