I am trying to add a clear button in the jquery datetimepicker widget using the below code.

], function ($, ko, Component) {
    'use strict';

    return Component.extend({
        initialize: function () {
               var holidaysarray = window.checkoutConfig.shipping.delivery_date.holidaysarray;
            ko.bindingHandlers.datetimepicker = {
                init: function (element, valueAccessor, allBindingsAccessor) {
                    var $el = $(element);
                    //initialize datetimepicker
                    var options = {
                             beforeShowDay: function(date) {
                                var formateddatestring = jQuery.datepicker.formatDate('yy-mm-dd', date);
                                return [ holidaysarray.indexOf(formateddatestring) == -1 ];
                            beforeShow: function (input) { 



                    var writable = valueAccessor();
                    if (!ko.isObservable(writable)) {
                        var propWriters = allBindingsAccessor()._ko_property_writers;
                        if (propWriters && propWriters.datetimepicker) {
                            writable = propWriters.datetimepicker;
                        } else {
                update: function (element, valueAccessor) {
                    var widget = $(element).data("DateTimePicker");
                    //when the view model is updated, update the widget
                    if (widget) {
                        var date = ko.utils.unwrapObservable(valueAccessor());
                    setTimeout(function () {
                    var buttonPane = $(input)

                    $("<button>", {
                        text: "Clear",
                        click: function () { jQuery.datepicker._clearDate(input); }
                    }).appendTo(buttonPane).addClass("ui-datepicker-clear ui-state-default ui-priority-primary ui-corner-all");
                }, 1);

            return this;

I have added dpClearButton function but when run it give me error in console like Uncaught TypeError: this.dpClearButton is not a function



This is expected behaviour in JS because the context of this has changed.

When you declare a function as part of an object the context of this switches to be the object itself, this example I've just created in the console should explain:

enter image description here

First of all I log this which is the Window object.

Then I create an object that contains a function which console logs this, you'll notice when I run that this is now actually set to the testObject object I created.


To workaround this you can store the previous context of this before it gets changed.

To do so add this to the first line of your init function:

var self = this;

Then change your function call to be:

  • added var self = this; in init function but now i am getting Cannot read property 'dpClearButton' of undefined – Zaheerabbas Mar 18 '20 at 4:09
  • If self isn't defined then you must have declared it in the wrong place, can you send your updated code please? – Ben Crook Mar 18 '20 at 10:10
  • Here is my code jsfiddle.net/u10rc46n – Zaheerabbas Mar 18 '20 at 10:22
  • also i am getting issue for required.on first load it validate but when i select day and clear it with button from panel it never validate again. – Zaheerabbas Mar 18 '20 at 10:27
  • Your problem looks to be you declared the self variable as a jQuery object, it should be var self = this; – Ben Crook Mar 18 '20 at 11:47

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