Knockout register inserted element with other function - javascript

I am using Knockout to display some tags for an array of images. each tag will have a popup that gives more information about the tag. The elements is registered with popup class the following way:
function RegisterCharacterPopups() {
$('[data-characterid]').each(function() {
var cId = $(this).data('characterid');
var placement = $(this).data('position');
if (placement == null || placement == undefined) {
placement = "top-center";
}
$(this).PopUp({
url: "/Ajax/CharacterPop/" + cId,
position: placement,
});
});
}
And i have added this to my constructor of the view model that contains the tags:
// Hook on to update of Tags
ko.computed(() => {
var test = this.Tags();
RegisterCharacterPopups();
console.log("Tags updated");
});
I can see the methods is executed, but the tags do not register with the popup. if it force the Tags to update again, will it work though!
I think the problem is that this method in executed the first time, before the elements are in the html.
How can I fix this, so it will wait for the elements to be inserted before it executes it?

Solution: a custom binding
ko.bindingHandlers['tagpop'] = {
init: function (element, valueAccessor, allBindings, vm, context) {
var data = valueAccessor();
$(element).PopUp({
url: "/Ajax/CharacterPop/" + data.id,
position: data.placement,
});
},
update: function (element, valueAccessor) {
}
};

Related

Knockout binding and CK Editor toolbar not appearing

I am totally new to knock-out custom binding, I am trying to integrate ckeditor with knock-out biding, I have the following binding got from Google search,
ko.bindingHandlers.wysiwyg = {
init: function (element, valueAccessor, allBindingsAccessor, viewModel) {
var value = valueAccessor();
var valueUnwrapped = ko.unwrap(value);
var allBindings = allBindingsAccessor();
var $element = $(element);
$element.attr('contenteditable', true);
if (ko.isObservable(value)) {
var isSubscriberChange = false;
var isEditorChange = true;
$element.html(value());
var isEditorChange = false;
$element.on('input, change, keyup, mouseup', function () {
if (!isSubscriberChange) {
isEditorChange = true;
value($element.html());
isEditorChange = false;
}
});
value.subscribe(function (newValue) {
if (!isEditorChange) {
isSubscriberChange = true;
$element.html(newValue);
isSubscriberChange = false;
}
});
}
}
}
I have the following code to bind,
$(function () {
$.getJSON("/getdata", function (data) {
ko.applyBindings({
testList: [{
test: ko.observable()
},
{
test: ko.observable()
}]
}, document.getElementById('htmled'));
});
});
HTML as follows
<div id="htmled" data-bind="foreach:testList">
Data
<div class="editor" data-bind="wysiwyg: test">Edit this data</div>
</div>
The binding works and show the toolbar when I call the ko.applyBindings outside the $.getJSON method. But when I call applyBindings inside, the toolbars not appearing. Can any body help me on this? I must be missing something for sure, any help on this is greatly appreciated.
Jsfiddle Added
Working :http://jsfiddle.net/jogejyothish/h4Lt3/1/
Not Working : http://jsfiddle.net/jogejyothish/Se8yR/2/
Jyothish
What's happening is this:
Your page loads with the single div. KO has yet to be applied to this div.
document.ready() fires. The CKEditor script applied CKEditor to any matching divs (none).
You make your ajax call.
The Ajax call completes. You apply bindings.
KO inserts two new divs, neither of which has CKEditor.
In order to fix it, you need to add some code inside your ajax success function to manually initialise the CKEditors, like:
$(".editor").each(function(idx, el) {
CKEDITOR.inline(el)
});
Here it is, working in your fiddle:
http://jsfiddle.net/Se8yR/5/
The reason your working version works is because the bindings are applied in document.ready, so KO renders the two div elements in time, and the CKEditor is successfully applied to them.
CKEditor takes some time to load.
In your first example, it loads after ko applies, which works fine.
In the second example, it loads before ko applies. The problem is that CKEditor looks for the contenteditable attribute which you set with ko, so the editor is not created.
You can create it manually with:
CKEDITOR.inline(element).setData(valueUnwrapped || $element.html());
Doc
Demo

TinyMCE with knockout data binding would´t update

I have the TinyMCE WYSiWYG Editor presenting text depending on a selected object, but experience problem with the binding.
The first "instanciation" seems to work, but when choosing a new text from the drop down list of available text the editor goes blank and Firebug console tells me:
TypeError: D.hasChildNodes is not a function
...ute(i),"string"==typeof r){try{r="true"===r?!0:"false"===r?!1:"null"===r?null:+r...
and
NS_ERROR_UNEXPECTED: Unexpected error
.../,"$1"));return false}});if(!u.getParam("accessibility_focus")){g.add(i.add(k,"a...
I have tried to recreate my code here: http://jsfiddle.net/xc4sz/1/
It´s not 100% but at least it does´t work. ;)
If I instead of clicking directly from text 1 to text 2 go via the "Choose option" the text is presented properly.
I guess it has to do with the "init" section below:
ko.bindingHandlers.tinymce = {
init: function (element, valueAccessor, allBindingsAccessor, context) {
var options = allBindingsAccessor().tinymceOptions || {};
var modelValue = valueAccessor();
var value = ko.utils.unwrapObservable(valueAccessor());
var el = $(element)
//handle edits made in the editor. Updates after an undo point is reached.
options.setup = function (ed) {
console.log(ed)
ed.onChange.add(function (ed, l) {
if (ko.isWriteableObservable(modelValue)) {
modelValue(l.content);
}
});
};
//handle destroying an editor
ko.utils.domNodeDisposal.addDisposeCallback(element, function () {
setTimeout(function () { $(element).tinymce().remove() }, 0)
});
//$(element).tinymce(options);
setTimeout(function () { $(element).tinymce(options); }, 0);
el.html(value);
},
update: function (element, valueAccessor, allBindingsAccessor, context) {
var $element = $(element),
value = ko.utils.unwrapObservable(valueAccessor()),
id = $element.attr('id');
//handle programmatic updates to the observable
// also makes sure it doesn't update it if it's the same.
// otherwise, it will reload the instance, causing the cursor to jump.
if (id !== undefined) {
var tinymceInstance = tinyMCE.get(id);
if (!tinymceInstance)
return;
var content = tinymceInstance.getContent({ format: 'raw' });
if (content !== value) {
$element.val(value);
//this should be more proper but ctr+c, ctr+v is broken, above need fixing
//tinymceInstance.setContent(value,{ format: 'raw' })
}
}
}
};
Depending on the versions of TinyMCE and jQuery that you are dependent on, you might like to try the custom binding I've recently rolled myself.
It's available on GitHub and NuGet
I found the issue. What happened was this:
you select Textbatch #1 and make some changes
you switch to Textbatch #2
the binding changes correctly from Textbatch #1 to #2
THEN the ed.onChange.add event handler kicks in and overwrites the content of the previous Textbatch #1 with that of the new Textbatch #2
Take a look at this updated fiddle (remove /show/light from the URL to get back to the editor). I had to inline select2.js, because Github does not allow files it hosts to be included remotely, causing your fiddle to fail.
The important part is in ko.utils.domNodeDisposal.addDisposeCallback:
ko.utils.domNodeDisposal.addDisposeCallback(element, function () {
$(element).tinymce().onChange.remove(changeHandler);
setTimeout(function () { $(element).tinymce().remove() }, 0)
});
I do not know why the removal of the editor is minimally delayed with a 0-second timeout, but there is probably a good reason for that. So all we do is remove the 'change' handler, so that the old editor cannot update the bound valueAccessor in your viewmodel anymore.
EDIT: I just noticed that I fixed your fiddle, but not necessarily your original exception… here is to hoping that the two were related.

KnockoutJS/Bootstrap - Clearing modal form when closing modal using javascript

I have a Bootstrap Modal that contains a form for updating or creating an entity (Company in my example). Right now my issue is that if I view an entity using the modal, it doesn't clear out the fields when I close the modal by any means. Causing the form to still be populated if I then click a "Create" button, which should bring me up a blank modal.
How can I execute one of my ViewModels methods from just regular javascript? Here is some of my code:
function ViewModel() {
var self = this;
function CompanyViewModel(company) {
var self = this;
self.Id = company.CompanyId;
self.Name = company.Name;
}
function BlankCompanyViewModel() {
var self = this;
self.Id = 0;
self.Name = "";
}
self.company = ko.observable();
self.companies = ko.observableArray();
self.clearCurrentCompany = function() {
self.company(new BlankCompanyViewModel());
};
// Initialize the view-model
$.getJSON("/api/company", function(companies) {
$.each(companies, function(index, company) {
self.companies.push(new CompanyViewModel(company));
});
self.clearCurrentCompany();
});
}
Ideally I'd like to run ViewModel.clearCurrentCompany on the "Hidden" event of the modal like so:
$('#myModal').on('hidden', function() {
//Do something here, not sure what
});
I like to use a custom binding around a modal to make it open/close/display based on populating/clearing an observable.
Something like:
ko.bindingHandlers.modal = {
init: function(element, valueAccessor, allBindings, vm, context) {
var modal = valueAccessor();
//init the modal and make sure that we clear the observable no matter how the modal is closed
$(element).modal({ show: false, backdrop: 'static' }).on("hidden.bs.modal", function() {
if (ko.isWriteableObservable(modal)) {
modal(null);
}
});
//apply the template binding to this element
ko.applyBindingsToNode(element, { with: modal }, context);
return { controlsDescendantBindings: true };
},
update: function(element, valueAccessor) {
var data = ko.utils.unwrapObservable(valueAccessor());
//show or hide the modal depending on whether the associated data is populated
$(element).modal(data ? "show" : "hide");
}
};
You then use this against an observable. It acts like a with binding against that observable and shows/hides the modal based on whether the observable is populated.
Here is a sample that shows this in use and sets up a subscription where you could run custom code when the modal is closed. http://jsfiddle.net/rniemeyer/uf3DF/
function ViewModel() {
var self = this;
// your previous code
$('#myModal').on('hide', function() {
self.clearCurrentCompany();
});
}
Just like that. Note that you want hide, not hidden, because hidden fires only after the modal completely disappears. If a user opens a create before the previous view closes, it will still be populated.

jasmine-fixtures - DOM changes never seen

I've got two RequireJS modules, one for fetching data from an external service, one in charge of passing a callback to the first module.
Here is the first very basic module:
define(["jquery"], function($) {
return {
/**
* Retrieves all the companies that do not employs the provided employee
* #param employeeId ID of the employee
* #param successCallback callback executed on successful request completion
* #return matching companies
*/
fetchCompanies: function(employeeId, successCallback) {
var url = '/employees/' + employeeId + '/nonEmployers';
return $.getJSON(url, successCallback);
}
};
});
And the most interesting one, that will generate a new drop-down and inject it into the specified DOM element (this is the one under test):
define([
'jquery',
'vendor/underscore',
'modules/non-employers',
'text!tpl/employeeOption.tpl'], function($, _, nonEmployers, employeeTemplate) {
var updateCompanies = function(selectedEmployeeId, companyDropDownSelector) {
nonEmployers.fetchCompanies(selectedEmployeeId, function(data) {
var template = _.template(employeeTemplate),
newContents = _.reduce(data, function(string,element) {
return string + template({
value: element.id,
display: element.name
});
}, "<option value='-1'>select a client...</option>\n");
$(companyDropDownSelector).html(newContents);
});
};
return {
/**
* Updates the dropdown identified by companyDropDownSelector
* with the companies that are non employing the selected employee
* #param employeeDropDownSelector selector of the employee dropdown
* #param companyDropDownSelector selector of the company dropdown
*/
observeEmployees: function(employeeDropDownSelector, companyDropDownSelector) {
$(employeeDropDownSelector).change(function() {
var selectedEmployeeId = $(employeeDropDownSelector + " option:selected").val();
if (selectedEmployeeId > 0) {
updateCompanies(selectedEmployeeId, companyDropDownSelector);
}
});
}
};
});
I'm trying to test this last module, using Jasmine-fixtures and using waitsFor, to asynchronously check that the set-up test DOM structure has been modified. However, the timeout is always reached.
If you can spot what's wrong in the following test, I'd be most grateful (gist:https://gist.github.com/fbiville/6223bb346476ca88f55d):
define(["jquery", "modules/non-employers", "modules/pages/activities"], function($, nonEmployers, activities) {
describe("activities test suite", function() {
var $form, $employeesDropDown, $companiesDropDown;
beforeEach(function() {
$form = affix('form[id=testForm]');
$employeesDropDown = $form.affix('select[id=employees]');
$employeesDropDown.affix('option[selected=selected]');
$employeesDropDown.affix('option[value=1]');
$companiesDropDown = $form.affix('select[id=companies]');
$companiesDropDown.affix('option');
});
it("should update the company dropdown", function() {
spyOn(nonEmployers, "fetchCompanies").andCallFake(function(employeeId, callback) {
callback([{id: 42, name: "ACME"}, {id: 100, name: "OUI"}]);
});
activities.observeEmployees('#employees', '#companies');
$('#employees').trigger('change');
waitsFor(function() {
var companiesContents = $('#companies').html(),
result = expect(companiesContents).toContain('<option value="42">ACME</option>');
return result && expect(companiesContents).toContain('<option value="100">OUI</option>');
}, 'DOM has never been updated', 10000);
});
});
});
Thanks in advance!
Rolf
P.S.: replacing $(employeeDropDownSelector).change by $(employeeDropDownSelector).on('change', and/or wrapping the activities.observeEmployees call (and $('#employees').trigger('change');) with a domReady yields the same result
P.P.S.: this error is the cause -> SEVERE: runtimeError: message=[An invalid or illegal selector was specified (selector: '[id='employees'] :selected' error: Invalid selector: *[id="employees"] *:selected).] sourceName=[http://localhost:59811/src/vendor/require-jquery.js] line=[6002] lineSource=[null] lineOffset=[0].
P.P.P.S.: it seems HtmlUnit doesn't support CSS3 selectors (WTF?), and even forcing the latest published version as jasmine-maven-plugin dependency won't change anything...
Is there any way to change jasmine plugin runner ?
OK guys.
Solution found:
upgrade (if not already) to jasmine-maven-plugin v1.3.1.1 (or later)
configure phantomjs instead of this crappy HtmlUnit (add PhantomJS binaries to your project)
if you've got use of ':focus' selector in your code, beware of this bug, replace it with $(mySelector).get(0) == document.activeElement
also, do not forget to wrap your code blocks by run(function() { /* expect */ }) if they are positioned after and depend on your waitsFor condition.
Finally, all should be well.
See how is the test now:
define(["jquery",
"modules/nonEmployers",
"modules/pages/activities"], function($, nonEmployers, activities) {
describe("activities test suite", function() {
var $form, $employeesDropDown, $companiesDropDown;
beforeEach(function() {
$form = affix('form[id=testForm]');
$employeesDropDown = $form.affix('select[id=employees]');
$employeesDropDown.affix('option[selected=selected]');
$employeesDropDown.affix('option[value=1]');
$companiesDropDown = $form.affix('select[id=companies]');
$companiesDropDown.affix('option');
spyOn(nonEmployers, "fetchCompanies").andCallFake(function(employeeId, callback) {
callback([{id: 42, name: "ACME"}, {id: 100, name: "OUI"}]);
});
});
it("should update the company dropdown", function() {
$(document).ready(function() {
activities.observeEmployees('#employees', '#companies');
$('#employees option[selected=selected]').removeAttr("selected");
$('#employees option[value=1]').attr("selected", "selected");
$('#employees').trigger('change');
waitsFor(function() {
var dropDown = $('#companies').html();
return dropDown.indexOf('ACME') > 0 && dropDown.indexOf('OUI') > 0;
}, 'DOM has never been updated', 500);
runs(function() {
var dropDown = $('#companies').html();
expect(dropDown).toContain('<option value="42">ACME</option>');
expect(dropDown).toContain('<option value="100">OUI</option>');
});
});
});
});
});
Creating modules this way is really difficult. I'd recommend not using fixtures and not rendering anywhere actually. Instead using detached DOM elements to do all the work is much easier.
Imagine if your code looked closer to this:
define([
'jquery',
'vendor/underscore',
'modules/non-employers',
'text!tpl/employeeOption.tpl'], function($, _, nonEmployers, employeeTemplate) {
return {
init: function() {
this.$companies = $('<select class="js-companies"></select>');
},
render: function(data) {
var template = _.template(employeeTemplate),
newContents = _.reduce(data, function(string,element) {
return string + template({
value: element.id,
display: element.name
});
}, "<option value='-1'>select a client...</option>\n");
this.$companies.empty().append(newContents);
return this;
});
observeEmployees: function(employeeDropDownSelector) {
$(employeeDropDownSelector).change(function() {
var selectedEmployeeId = $(employeeDropDownSelector + " option:selected").val();
if (selectedEmployeeId > 0) {
nonEmployers.fetchCompanies(selectedEmployeeId, function(data) {
this.render(data);
}
}
});
}
};
});
The above is not complete. It is just to give you an idea of another way to approach your problem. Now instead of a fixture all you need to do is inspect this.$companies and you will be done. I think the main problem though is that your functions are not simple enough. The concern of each function should be extremely specific. Your updateCompanies function is doing things like creating a template, fetching data then passing it to an anonymous function, which can't be spied on, that anonymous function iterates on an object, then you change some already existing DOM element. That sounds exhausting. All that function should do is look at some precompiled template send it an object. The template should loop on the object using {{each}} then return. Your function then empties and append the newContents and returns it self so the next function down can choose what it should do with this.$companies. Or if this.$companies has already been append to the page nothing needs to be done at all.

how to use datepicker with knockout [duplicate]

I'm trying to use KnockoutJS with jQuery UI. I have an input element with a datepicker attached. I'm currently running knockout.debug.1.2.1.js and it seems that the change event is never being caught by Knockout. The element looks like this:
<input type="text" class="date" data-bind="value: RedemptionExpiration"/>
I've even tried changing the valueUpdate event type but to no avail. It seems like Chrome causes a focus event just before it changes the value, but IE doesn't.
Is there some Knockout method that "rebinds all the bindings"? I technically only need the value changed before I send it back to the server. So I could live with that kind of workaround.
I think the problem's the datepicker's fault, but I can't figure out how to fix this.
Any ideas?
I think that for the jQuery UI datepicker it is preferable to use a custom binding that will read/write with Date objects using the APIs provided by the datepicker.
The binding might look like (from my answer here):
ko.bindingHandlers.datepicker = {
init: function(element, valueAccessor, allBindingsAccessor) {
//initialize datepicker with some optional options
var options = allBindingsAccessor().datepickerOptions || {},
$el = $(element);
$el.datepicker(options);
//handle the field changing by registering datepicker's changeDate event
ko.utils.registerEventHandler(element, "changeDate", function () {
var observable = valueAccessor();
observable($el.datepicker("getDate"));
});
//handle disposal (if KO removes by the template binding)
ko.utils.domNodeDisposal.addDisposeCallback(element, function() {
$el.datepicker("destroy");
});
},
update: function(element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor()),
$el = $(element);
//handle date data coming via json from Microsoft
if (String(value).indexOf('/Date(') == 0) {
value = new Date(parseInt(value.replace(/\/Date\((.*?)\)\//gi, "$1")));
}
var current = $el.datepicker("getDate");
if (value - current !== 0) {
$el.datepicker("setDate", value);
}
}
};
You would use it like:
<input data-bind="datepicker: myDate, datepickerOptions: { minDate: new Date() }" />
Sample in jsFiddle here: http://jsfiddle.net/rniemeyer/NAgNV/
Here is a version of RP Niemeyer's answer that will work with the knockout validation scripts found here: http://github.com/ericmbarnard/Knockout-Validation
ko.bindingHandlers.datepicker = {
init: function (element, valueAccessor, allBindingsAccessor) {
//initialize datepicker with some optional options
var options = allBindingsAccessor().datepickerOptions || {};
$(element).datepicker(options);
//handle the field changing
ko.utils.registerEventHandler(element, "change", function () {
var observable = valueAccessor();
observable($(element).val());
if (observable.isValid()) {
observable($(element).datepicker("getDate"));
$(element).blur();
}
});
//handle disposal (if KO removes by the template binding)
ko.utils.domNodeDisposal.addDisposeCallback(element, function () {
$(element).datepicker("destroy");
});
ko.bindingHandlers.validationCore.init(element, valueAccessor, allBindingsAccessor);
},
update: function (element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor());
//handle date data coming via json from Microsoft
if (String(value).indexOf('/Date(') == 0) {
value = new Date(parseInt(value.replace(/\/Date\((.*?)\)\//gi, "$1")));
}
current = $(element).datepicker("getDate");
if (value - current !== 0) {
$(element).datepicker("setDate", value);
}
}
};
Changes are to the change event handler to pass the entered value and not the date to the validation scripts first, then only setting the date to the observable if it is valid. I also added the validationCore.init that is needed for custom bindings discussed here:
http://github.com/ericmbarnard/Knockout-Validation/issues/69
I also added rpenrose's suggestion for a blur on change to eliminate some pesky datepicker scenarios getting in the way of things.
I've used a different approach. Since knockout.js doesn't seem to fire the event on change, I've forced the datepicker to call change() for its input once closed.
$(".date").datepicker({
onClose: function() {
$(this).change(); // Forces re-validation
}
});
Although all of these answers saved me a lot of work, none of them fully worked for me. After selecting a date, the binded value would not update. I could only get it to update when changing the date value using the keyboard then clicking out of the input box. I fixed this by augmenting RP Niemeyer's code with syb's code to get:
ko.bindingHandlers.datepicker = {
init: function (element, valueAccessor, allBindingsAccessor) {
//initialize datepicker with some optional options
var options = allBindingsAccessor().datepickerOptions || {};
var funcOnSelectdate = function () {
var observable = valueAccessor();
observable($(element).datepicker("getDate"));
}
options.onSelect = funcOnSelectdate;
$(element).datepicker(options);
//handle the field changing
ko.utils.registerEventHandler(element, "change", funcOnSelectdate);
//handle disposal (if KO removes by the template binding)
ko.utils.domNodeDisposal.addDisposeCallback(element, function () {
$(element).datepicker("destroy");
});
},
update: function (element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor());
if (typeof(value) === "string") { // JSON string from server
value = value.split("T")[0]; // Removes time
}
var current = $(element).datepicker("getDate");
if (value - current !== 0) {
var parsedDate = $.datepicker.parseDate('yy-mm-dd', value);
$(element).datepicker("setDate", parsedDate);
}
}
};
I suspect putting the observable($(element).datepicker("getDate")); statement in its own function and registering that with options.onSelect did the trick?
Thanks for this article I found it very useful.
If you want the DatePicker to behave exactly like the JQuery UI default behaviour I recommend adding a blur on the element in the change event handler:
i.e.
//handle the field changing
ko.utils.registerEventHandler(element, "change", function () {
var observable = valueAccessor();
observable($(element).datepicker("getDate"));
$(element).blur();
});
I solved this problem by changing the order of my included script files:
<script src="#Url.Content("~/Scripts/jquery-ui-1.10.2.custom.js")"></script>
<script src="#Url.Content("~/Scripts/knockout-2.2.1.js")"></script>
Same as RP Niemeyer, but better support of WCF DateTime, Timezones and Using the DatePicker onSelect JQuery property.
ko.bindingHandlers.datepicker = {
init: function (element, valueAccessor, allBindingsAccessor) {
//initialize datepicker with some optional options
var options = allBindingsAccessor().datepickerOptions || {};
var funcOnSelectdate = function () {
var observable = valueAccessor();
var d = $(element).datepicker("getDate");
var timeInTicks = d.getTime() + (-1 * (d.getTimezoneOffset() * 60 * 1000));
observable("/Date(" + timeInTicks + ")/");
}
options.onSelect = funcOnSelectdate;
$(element).datepicker(options);
//handle the field changing
ko.utils.registerEventHandler(element, "change", funcOnSelectdate);
//handle disposal (if KO removes by the template binding)
ko.utils.domNodeDisposal.addDisposeCallback(element, function () {
$(element).datepicker("destroy");
});
},
update: function (element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor());
//handle date data coming via json from Microsoft
if (String(value).indexOf('/Date(') == 0) {
value = new Date(parseInt(value.replace(/\/Date\((.*?)\)\//gi, "$1")));
}
current = $(element).datepicker("getDate");
if (value - current !== 0) {
$(element).datepicker("setDate", value);
}
}
};
Enjoy :)
http://jsfiddle.net/yechezkelbr/nUdYH/
I think it can be done much easier: <input data-bind="value: myDate, datepicker: myDate, datepickerOptions: {}" />
So you do not need manual change handling in init function.
But in this case, your 'myDate' variable will get only visible value, not Date object.
Alternatively, you can specify this in binding:
Update:
function (element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor()),
current = $(element).datepicker("getDate");
if (typeof value === "string") {
var dateValue = new Date(value);
if (dateValue - current !== 0)
$(element).datepicker("setDate", dateValue);
}
}
Based on Ryan's solution, myDate returns the standard date string, which is not the ideal one in my case. I used date.js to parse the value so it will always return the date format you want. Take a look at this example fiddle Example.
update: function(element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor()),
current = $(element).datepicker("getDate");
var d = Date.parse(value);
if (value - current !== 0) {
$(element).datepicker("setDate", d.toString("MM/dd/yyyy"));
}
}
I needed to repeatedly update my data from the server came across this but didn't quite finish the job for my needs sharing below(my date format /Date(1224043200000)/):
//Object Model
function Document(data) {
if (String(data.RedemptionExpiration).indexOf('/Date(') == 0) {
var newDate = new Date(parseInt(data.BDate.replace(/\/Date\((.*?)\)\//gi, "$1")));
data.RedemptionExpiration = (newDate.getMonth()+1) +
"/" + newDate.getDate() +
"/" + newDate.getFullYear();
}
this.RedemptionExpiration = ko.observable(data.RedemptionExpiration);
}
//View Model
function DocumentViewModel(){
///additional code removed
self.afterRenderLogic = function (elements) {
$("#documentsContainer .datepicker").each(function () {
$(this).datepicker();
});
};
}
After the model is formatted correctly for the output I added a template with the documentation knockoutjs:
<div id="documentsContainer">
<div data-bind="template: { name: 'document-template', foreach: documents, afterRender: afterRenderLogic }, visible: documents().length > 0"></div>
</div>
//Inline template
<script type="text/html" id="document-template">
<input data-bind="value: RedemptionExpiration" class="datepicker" />
</script>
Few people asked for dynamic datepicker options. In my case I needed a dynamic date range - so the first input defines the min value of the second and the second sets the max value for the first. I solved it by extending the RP Niemeyer's handler. So to his original:
ko.bindingHandlers.datepicker = {
init: function(element, valueAccessor, allBindingsAccessor) {
//initialize datepicker with some optional options
var options = allBindingsAccessor().datepickerOptions || {},
$el = $(element);
$el.datepicker(options);
//handle the field changing by registering datepicker's changeDate event
ko.utils.registerEventHandler(element, "change", function() {
var observable = valueAccessor();
observable($el.datepicker("getDate"));
});
//handle disposal (if KO removes by the template binding)
ko.utils.domNodeDisposal.addDisposeCallback(element, function() {
$el.datepicker("destroy");
});
},
update: function(element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor()),
$el = $(element);
//handle date data coming via json from Microsoft
if (String(value).indexOf('/Date(') == 0) {
value = new Date(parseInt(value.replace(/\/Date\((.*?)\)\//gi, "$1")));
}
var current = $el.datepicker("getDate");
if (value - current !== 0) {
$el.datepicker("setDate", value);
}
}
};
I've added two more handlers corresponding to the options I wanted to modify:
ko.bindingHandlers.minDate = {
update: function(element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor()),
current = $(element).datepicker("option", "minDate", value);
}
};
ko.bindingHandlers.maxDate = {
update: function(element, valueAccessor) {
var value = ko.utils.unwrapObservable(valueAccessor()),
current = $(element).datepicker("option", "maxDate", value);
}
};
And used them like that in my template:
<input data-bind="datepicker: selectedLowerValue, datepickerOptions: { minDate: minValue()}, maxDate: selectedUpperValue" />
<input data-bind="datepicker: selectedUpperValue, datepickerOptions: { maxDate: maxValue()}, minDate: selectedLowerValue" />
Using custom bindings provided in previous answers is not always possible. Calling $(element).datepicker(...) takes some considerable time, and if you have, for example, a few dozens, or even hundreds of elements to call this method with, you have to do it "lazy", i.e. on demand.
For example, the view model may be initialized, the inputs being inserted into the DOM, but the corresponding datepickers will only be initialized when a user clicks them.
So, here is my solution:
Add a custom binding that allows to attach arbitrary data to a node:
KO.bindingHandlers.boundData = {
init: function(element, __, allBindings) {
element.boundData = allBindings.get('boundData');
}
};
Use the binding to attcah the observable used for the input's value:
<input type='text' class='my-date-input'
data-bind='textInput: myObservable, boundData: myObservable' />
And finally, when initializing the datepicker, use it's onSelect option:
$('.my-date-input').datepicker({
onSelect: function(dateText) {
this.myObservable(dateText);
}
//Other options
});
This way, every time a user changes the date with the datepicker, the corresponding Knockout observable is also updated.

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