Develop Reference

Knockout bindings from JSON file issues

I am using Typescript to define my Knockout ViewModel.
I have a JSON file, the structure of which can be seen here (Github gist as It's a bit large to paste here).
The structure is basically:
OrderLine (the root) -> milestones -> factory_date
Or orally: (many) order lines have (many) milestones, which each have (one) factory date.
I am trying to build a ViewMOdel with the following:
var FactoryAppViewModel = (function () {
function FactoryAppViewModel(seasonID) {
var self = this;
self.seasonID = seasonID;
self.orderlines = ko.observableArray([]);
this.buildViewModel();
}
FactoryAppViewModel.prototype.buildViewModel = function () {
var self = this;
var getOrderLines = HTTP.get("/season/" + self.seasonID + "/orderlines").done(function (data) {
self.orderlines(JSON.parse(data));
}).fail(function () {
error("Could not get orderlines");
});
};
As far as I know, the JSON.parse on the data here will apply the values to the orderlines ko.observableArray([]), However I need to apply a ko.observable to the order lines children (milestones), and to a milestones child (factory_date) as well. And I don't know how to do this. Least of all from JSON.
I have read this but it didn't seem to help me.
I know that the observable isn't applied, because when i change a factory_date in the view, it doesn't update the viewmodel.
Any help would be appreciated. The javascript above is the compiled TypeScript.
EDIT:
Here is an example of the way I'm accessing the code in the view:
<tbody data-bind="foreach: orderlines">
<tr>
<td data-bind="text: factory.name"></td>
<!-- ko foreach: milestones -->
<!-- ko if: factory_date == null -->
<td>
<span>TBA</span>
</td>
<!-- /ko -->
<!-- ko if: factory_date !== null -->
<td>
<div class="wrapper-wrapper">
<div class="btn btn-primary dateChanger">
<span data-bind="text: moment(factory_date.milestone_date).format('DD-MM-YYYY')"></span>
</div>
<div class="date-update-wrapper text-center">
<input type="text" data-bind="attr: {value: moment(factory_date.milestone_date).format('DD-MM-YYYY')}" class="form-control datetimepicker">
<a class="save-date btn btn-success" data-bind="click: function(){$root.saveDate(factory_date, $parent)}"><i class="fa fa-check"></i></a>
<a class="cancel-date btn btn-danger"><i class="fa fa-times"></i></a>
</div>
</div>
</td>
<!-- /ko -->
<!-- /ko -->
</tr>
</tbody>
The part that made me aware I had an issue was this part:
data-bind="click: function(){$root.saveDate(factory_date, $parent)}"
I made a simple saveDate method, which was console.log(factory_date.milestone_date), and it returned the default JSON data, despite me editing it in the view (using the datepicker).

Knockout does not map children in lists to observables by default. There is a plugin called ko.mapping that can help you achieve what you are looking for.
You can set up a "children" mapping, or loop through your children, manually making them observable (In this case from JavaScript):
var mappedChildren = [];
var children = someObj.children();
for (var i = 0; i < children.length; i++) {
var mappedChild = ko.mapping.fromJS(children[i], mappingFunction);
mappedChildren.push(mappedChild);
}
someObj.children(mappedChildren);

Knockout view not removing item from view after delete

I have this code that successfully deletes an exam from a list of exams displayed on a page, but the page still shows the deleted exam. You have to manually refresh the page for the view to update. We are using a simlar pattern on other pages and it's working correctly. I don't understand why it doesn't work on this page.
// Used to handle the click event for Delete
remove = (exam: Models.Exam) => {
$("#loadingScreen").css("display", "block");
var examService = new Services.ExamService();
examService.remove(exam.examId()).then(() => {
examService.getByFid().then((examinations: Array<Models.Exam>) => {
this.exams(examinations);
this.template("mainTemplate");
});
}).fail((error: any) => {
// Add this error to errors
this.errors([error]);
window.scrollTo(0, 0);
}).fin(() => {
$("#loadingScreen").css("display", "none");
});
}
Here's the UI code that displays the list of exams
<div class="section module">
<!-- ko if: exams().length > 0 -->
<!-- ko foreach: exams.sort(function(a,b){return a.mostRecentDateTaken() > b.mostRecentDateTaken() ? 1:-1}) -->
<div class="addremove_section bubbled">
<a class="button open_review" data-bind="click: $root.edit">Edit</a>
<a class="button open_review" data-bind="click: $root.remove">Delete</a>
<div class="titleblock">
<h4 data-bind="text: 'Exam Name: ' + examTypeLookup().examTypeName()"></h4>
<div data-bind="if:examEntityLookup()!=null">
<div data-bind=" text: 'Reporting Entity: ' + examEntityLookup().description()"></div>
</div>
<div data-bind="text: 'Most recent date taken: ' + $root.formatDate(mostRecentDateTaken())"></div>
<div data-bind="text: 'Number of attempts: ' + numberOfAttempts()"></div>
<div data-bind="text: 'Pass/Fail Status: ' + $root.PassFailEnum(passFailId())"></div>
</div>
<div class="clearfix"></div>
</div>
<!-- /ko -->
<!-- /ko -->
<!-- ko if: exams().length == 0 -->
<div class="addremove_section bubbled">
<div class="titleblock">
<div>No Exams Have Been Entered.</div>
</div>
</div>
<!-- /ko -->
</div>
EDIT: I discovered that if I remove the sort from this line in the view
<!-- ko foreach: exams.sort(function(a,b){return a.mostRecentDateTaken() > b.mostRecentDateTaken() ? 1:-1}) -->
to
<!-- ko foreach: exams -->
it works! The only problem is that I need the data sorted.

I removed the sorting from the view and did the sorting in the service. Not really sure why I can't sort in the view. I assume it's a knockout.js bug.
<!-- ko foreach: exams -->
[HttpGet]
[Route("api/exam")]
public IEnumerable<TDto> GetApplicantExams()
{
var dtos = GetCollection(() => _examService.GetApplicantExams(UserContext.Fid).OrderBy(e => e.DateTaken));
return dtos.ForEach(t => AddItems(t));
}

It's not a bug in Knockout. Since the sort invocation (as you're doing it) is not under the control of a computed/dependent observable, there's nothing to trigger it to resort. You've basically broken the connection between the UI (or more technically, the bindingHandler) and the ko.observable which KO uses for tracking changes.
I've run into this many times where I work, and the general pattern I use is something like this:
var viewmodel = {
listOfObjects:ko.observableArray(),
deleteFromList:deleteFromList,
addToList:addToList,
}
//in your HTML, you'll do a foreach: listOfSortedObjects (instead of listOfObjects)
viewmodel.listOfSortedObjects = ko.computed(function(){
//Since this is *inside* the change tracking ecosystem, this sort will be called as you would expect
return viewmodel.listOfObjects().sort(yourSortingFunction);
});
//Since you cannot edit a (normal) computed, you need to do your work on the original array as below.
function deleteFromList(item){
viewmodel.listOfObjects.remove(item);//Changing this array will trigger the sorted computed to update, which will update your UI
}
function addToList(item){
viewmodel.listOfObjects.push(item);
}

Knockout conditional binding (but not the native "if" way)

I have a case that look like this (excessively simplified):
<!-- ko if: readOnly() -->
<a href="url" data-bind="click: ToggleReadOnly()" />
<!-- /ko -->
<!-- ko ifnot: readOnly() -->
<a href="url" data-bind="visible: someObservable" />
<!-- /ko -->
Because of multiple other things around that would multiply the tests and duplicate a lot of code, I'd need to be able to do this in one line, something like:
<a href="url" data-bind="if: readOnly() { click: ToggleReadOnly() } else: { visible: someObservable }" />
Is there a way to do that ?

There are a couple of approaches you could take to this. Each with it's own strengths and weaknesses. but I will focus on using templates.
Create a template for each state where it is rendered in readonly mode or not. You'll only need to add to your model a function that decides which template to use.
<script type="text/html" id="template-readonly-link">
ReadOnly
</script>
<script type="text/html" id="template-readwrite-link">
ReadWrite
</script>
<!-- ko template: { name: selectTemplate } --><!-- /ko -->
function ViewModel() {
this.readOnly = ko.observable(true);
this.someObservable = ko.observable(true);
this.ToggleReadOnly = function (data, event) {
this.readOnly(!this.readOnly());
return false;
}.bind(this);
this.selectTemplate = function (data) {
return this.readOnly()
? 'template-readonly-link'
: 'template-readwrite-link';
}.bind(this);
}
fiddle
You can explore other approaches such as custom components, custom bindings, etc. But this may be the easiest to implement.

Filter Data Using Knockout JS

I have static array that have 2 set of data.
I have make 2 part of the one div and on right side show all list from array and on left side nothing.
On right side have put + sign on button, on it's click that record came on left side div and working fine and at that time the plus sign become minus when that record came on left side, when click on minus sign again that record removed from left side. Just like toggle.
Now I want to filter the right side of list using textbox.
It will search on 2 columns i.e. code and title.
but how to make filter I don't know.
HTML Code :
<div class="col-md-6">
<div class="col-md-4">
<input type="text" required id="filterD" class="form-control" data-bind=""/>
</div>
<!-- ko foreach: controlFields -->
<div class="row">
<div class="col-md-11 table-bordered">
<div class="form-group" style="padding-top: 3px;">
<div class="col-md-2" data-bind="text:code">
</div>
<div class="col-md-7" data-bind="text:title">
</div>
<div class="col-md-1" data-bind="text:i1">
</div>
<div class="col-md-1" data-bind="text:i2">
</div>
<div>
<!-- ko ifnot : viewFlag -->
<button class="btn-primary btn-xs" data-bind="click: $root.addField">
<i class="glyphicon glyphicon-plus-sign"></i>
</button>
<!-- /ko -->
<!-- ko if : viewFlag -->
<button class="btn-primary btn-xs" data-bind="click: $root.removeField">
<i class="glyphicon glyphicon-minus-sign"></i>
</button>
<!-- /ko -->
</div>
</div>
<!-- ko foreach: subFields -->
<div style="padding-top: 3px" class="form-group" data-bind="attr:{'title':description()}">
<div class="col-md-2">
</div>
<div style="border-top: 1px solid #ddd; " class="col-md-2" data-bind="text:code">
</div>
<div style="border-top: 1px solid #ddd; " class="col-md-7" data-bind="text:title">
</div>
<div>
<button class="btn-primary btn-xs"><i class="glyphicon glyphicon-plus-sign"></i></button>
</div>
</div>
<!-- /ko -->
</div>
</div>
<br />
<!-- /ko -->
</div>
JavaScript :
var exports = {},
ViewModel, ControlField , SubField;
SubField = function(code, title,data,description){
var self = this;
self.code = ko.observable(code);
self.title = ko.observable(title);
self.data = ko.observable(data);
self.description = ko.observable(description);
};
ControlField = function(code, title, i1, i2){
var self = this;
self.code = ko.observable(code);
self.title = ko.observable(title);
self.i1 = ko.observable(i1);
self.i2 = ko.observable(i2);
self.subFields = ko.observableArray([]);
self.viewFlag = ko.observable(false);
};
ViewModel = function(data) {
var self = this;
self.controlFields = ko.observableArray([]);
var controlField = new ControlField("100","BookTitle","0","1");
self.controlFields.push(controlField);
controlField.subFields().push(new SubField("a","Title","JAVA","For Entering Item Title Data"));
controlField.subFields().push(new SubField("p","Section","2","For Section"));
var controlField1 = new ControlField("245","Author","1","0");
self.controlFields.push(controlField1);
controlField1.subFields().push(new SubField("a","Name","Herbert","Name of The Author"));
controlField1.subFields().push(new SubField("d","Place","Ontario","Place of Author"));
self.addField = function(field){
field.viewFlag(true);
};
self.removeField = function(field){
field.viewFlag(false);
};
};
I want that when I type any character in input=text it will filter data and then show.
Any suggestion on this.
Here's Screen of this code :

You can use ko.computed for filtering the data.
//filter html binding
<input type="text" required id="filterD" class="form-control" data-bind="value:filter,valueUpdate: 'keyup'" />// use valueUpdate binding
//bind filter to filter text
self.filter = ko.observable();
//Use filteredList in html binding instead of controlFields
self.filteredList = ko.computed(function () {
var filter = self.filter(),
arr = [];
if (filter) {
ko.utils.arrayForEach(self.controlFields(), function (item) {
if (item.code() == filter || item.title() == filter) {
arr.push(item);
}
});
} else {
arr = self.controlFields();
}
return arr;
});
Fiddle Demo
//sorry for ui part(Html alignment) in demo.

How to remove items from external observableArray with KnockoutJS

The goal
Remove items from external observableArray using KnockoutJS.
The problem
There is two observableArray in my application. One for available products to buy and other to products that I have added in the Summary by clicking in add button.
Until here, all works fine. But now I need to remove items from Summary and change the button state/style — and I do not know how to access an external observableArray to do this.
To understand my problem, check out this jsFiddle or see the markup in the next topic.
As you could see, when I click on add button, the product goes to Summary. When I click on remove — regardless if the button is from the summary or the product — I want to change the button state and remove the item from summary. Technically speaking, I want to remove the item from items' observableArray utilizing the products' observableArray.
My code
HTML:
<ul class="summary">
<!-- ko foreach: Summary.items -->
<p data-bind="text: name"></p>
<button class="btn btn-danger btn-mini remove-item">
<i class="icon-remove">×</i>
</button>
<!-- /ko -->
</ul>
<h1>What would you to buy?</h1>
<ul class="products">
<!-- ko foreach: Product.products -->
<li>
<h3 data-bind="text: name"></h3>
<p data-bind="text: desc"></p>
<!-- ko if:isAdded -->
<button data-bind="if: isAdded" class="btn btn-small btn-success action remove">
<i data-bind="click: $root.Summary.remove" class="icon-ok">Remove</i>
</button>
<!-- /ko -->
<!-- ko ifnot:isAdded -->
<form data-bind="submit: function() { $root.Summary.add($data); }">
<button data-bind="ifnot: isAdded" class="btn btn-small action add">
<i class="icon-plus">Add</i>
</button>
</form>
<!-- /ko -->
</li>
<!-- /ko -->
</ul>
JavaScript:
function Product(id, name, desc) {
var self = this;
self.id = ko.observable(id);
self.name = ko.observable(name);
self.desc = ko.observable(desc);
self.isAdded = ko.observable(false);
}
function Item(id, name) {
var self = this;
self.id = ko.observable(id);
self.name = ko.observable(name);
}
function SummaryViewModel() {
var self = this;
self.items = ko.observableArray([]);
self.add = function (item) {
self.items.push(new Item(item.id(), item.name()));
console.log(item);
item.isAdded(true);
};
self.remove = function (item) {
item.isAdded(false);
};
};
function ProductViewModel(products) {
var self = this;
self.products = ko.observableArray(products);
};
var products = [
new Product(1, "GTA V", "by Rockstar"),
new Product(2, "Watch_Dogs", "by Ubisoft")
];
ViewModel = {
Summary: new SummaryViewModel(),
Product: new ProductViewModel(products)
}
ko.applyBindings(ViewModel);

You can search for it.
You can query the cart for an item with the same id, and remove it
self.remove = function (item) {
var inItems = self.items().filter(function(elem){
return elem.id() === item.id(); // find the item with the same id
})[0];
self.items.remove(inItems);
item.isAdded(false);
};
Unless you have hundreds of thousands of items, that should be perfectly fast enough. Just remember to use items.remove() so it'll know to update the observableArray :)

Once you've declared products as an observableArray, you should just be able to call remove on it (according to this). Given you have a reference to the object being deleted to pass in.