Passing values to ko.computed in Knockout JS - javascript

I've been working for a bit with MVC4 SPA, with knockoutJs,
My problem is I want to pass a value to a ko.computed. Here is my code.
<div data-bind="foreach: firms">
<fieldset>
<legend><span data-bind="text: Name"></span></legend>
<div data-bind="foreach: $parent.getClients">
<p>
<span data-bind="text: Name"></span>
</p>
</div>
</fieldset>
</div>
self.getClients = ko.computed(function (Id) {
var filter = Id;
return ko.utils.arrayFilter(self.Clients(), function (item) {
var fId = item.FirmId();
return (fId === filter);
});
});
I simply want to display the Firmname as a header, then show the clients below it.
The function is being called, but Id is undefined (I've tried with 'Firm' as well), if I change:
var filter = id; TO var filter = 1;
It works fine,
So... How do you pass a value to a ko.computed? It doesn't need to be the Id, it can also be the Firm object etc.

Each firm really should be containing a list of clients, but you could use a regular function I think and pass it the firm:
self.getClientsForFirm = function (firm) {
return ko.utils.arrayFilter(self.Clients(), function (item) {
var fId = item.FirmId();
return (fId === firm.Id());
});
});
Then in html, $data is the current model, in your case the firm:
<div data-bind="foreach: $root.getClientsForFirm($data)">

Knockout doesn't allow you pass anything to a computed function. That is not what it is for. You could instead just use a regular function there if you'd like.
Another option is to have the data already in the dataset on which you did the first foreach. This way, you don't use $parent.getClients, but more like $data.clients.

Related

KnockoutJS Observable being rebound appropriately, but calling gives an empty string?

So I've got a section that updates based on a ko.observable called toClicked, see below:
<div id="longInfoWindow">
<div id="longInfo_goBack"><span class="fa fa-arrow-left"></span> Go Back</div>
<div id="location_mainInfo">
<h1 id="location_title" data-bind="text: toClicked.title">Title</h1>
<h2 id="location_address" data-bind="text: toClicked.address">Address</h2>
<h6 class="location_latlng">LAT: <span data-bind="text: toClicked.lat">LATITUDE</span></h6>
<h6 class="location_latlng">LNG: <span data-bind="text: toClicked.lng">LONGITUDE</span></h6>
<p id="location_description" data-bind="text: toClicked.content">
Empty
</p>
</div>
</div>
toClicked is data-bound via a for-each ul that passes in bits of information from an observableArray, so this data is constantly changing - here's what the click function looks like in the viewmodel.
var viewModel = {
// Nav open and close via knockoutjs
self : this,
userQuery : ko.observable(''),
toClicked : ko.observable({}),
logClick : function(clicked){
var toClicked = ko.observable({});
toClicked().title = clicked.title;
toClicked().lat = clicked.lat;
toClicked().lng = clicked.lng;
toClicked().placeID = clicked.placeID;
toClicked().address = clicked.address;
toClicked().content = clicked.content;
return toClicked();
}
};
// at the end of the document...
ko.applyBindings(viewModel);
For some reason, I can call any toClicked parameter, like toClicked.title, and I get the proper output. But I can't get anything to bind in the longInfoWindow bit of code, it removes the filler text with empty strings. Is there something I'm missing here with Knockout that's keeping it from updating appropriately?
As a side note, I've tried setting the databinds to viewModel.toClicked.title with no joy. Have also tried $root, $parent. either comes back as not defined or gives the same result.
You need to change the way toClicked is accessed. Given that it is an observable, it must access the properties using syntax like toClicked().property. Another problem is that you should specify toClicked as an object, before setting properties on it.
Also, since clicked is an array, it should be accessed by index, like clicked[0].title.
Note the use of self.toClicked.valueHasMutated(); in function logClick. It tells the view model that observable variable toClicked has some non-observable properties that might have changed. As a result the view model is updated. You should avoid using it excessively.
var viewModel = function() {
// Nav open and close via knockoutjs
var self = this;
self.test = ko.observable('text');
self.userQuery = ko.observable('');
self.toClicked = ko.observable({});
self.markers = ko.observableArray([
{ title: 'Eagle River Airport', lat: 45.934099, lng: -89.261834, placeID: 'ChIJdSZITVA2VE0RDqqRxn-Kjgw', content: 'This is the Eagle River Airport. Visit us for fly-ins!' }
]);
self.logClick = function(clicked) {
// var toClicked = ko.observable({});
self.toClicked().title = clicked[0].title;
self.toClicked().lat = clicked[0].lat;
self.toClicked().lng = clicked[0].lng;
self.toClicked().placeID = clicked[0].placeID;
self.toClicked().address = clicked[0].address;
self.toClicked().content = clicked[0].content;
self.toClicked.valueHasMutated();
return self.toClicked();
};
};
// at the end of the document...
var vm = new viewModel();
ko.applyBindings(vm);
var markers = vm.markers();
vm.logClick(markers);
Your view model must also change slightly. Note the () brackets after toClicked, they are used to access the properties of an observable.
<div id="longInfoWindow">
<div id="longInfo_goBack"><span class="fa fa-arrow-left"></span> Go Back</div>
<div id="location_mainInfo">
<h1 id="location_title" data-bind="text: toClicked().title">Title</h1>
<h2 id="location_address" data-bind="text: toClicked().address">Address</h2>
<h6 class="location_latlng">LAT: <span data-bind="text: toClicked().lat">LATITUDE</span></h6>
<h6 class="location_latlng">LNG: <span data-bind="text: toClicked().lng">LONGITUDE</span></h6>
<p id="location_description" data-bind="text: toClicked().content">
Empty
</p>
</div>
I'd also suggest that instead of accessing toClicked directly within logClick you use something like self.toClicked to avoid ambiguity. See this.
Here's the working fiddle: https://jsfiddle.net/Nisarg0/hx0q6tt6/13/
The more obvious way without having to use valueHasMutated would be to assign directly to the observable:
self.logClick = function(clicked) {
self.toClicked({
lat: clicked[0].lat,
lng: clicked[0].lng,
placeID: clicked[0].placeID,
adress: clicked[0].address,
content: clicked[0].content
});
};
You normally do not need to use valueHasMutated when using knockout. Also there is no need to return the observable from the click handler. In your bindings you need then to access the properties as already stated like this:
<h1 id="location_title" data-bind="text: toClicked().title">Title</h1>
Knockout will automatically update the heading, whenever toClicked changed.

angular dynamic property name in nested ng-repeat

I'm wondering is there any way to add dynamically generated names in nested ng-repeat, for example:
<div ng-repeat="x in JSONfile">
<div ng-repeat="i in x.name">
<span><a ng-href="{{i.link}}">{{i.name}}</a></span>
</div>
</div>
JSONfile: returns some names,
x.name is dynamically generated from the mentioned JSONfile, and it should be used as a plain text like "NAME", if I add NAME instead of i.name I get the json file loaded, but i want it automatically loaded, because I don't know which of the names will come first.
the i.name returns this:
n
a
m
e
not "NAME" as it should..
So, the question is, is there any way to tell angular that i want this dynamically generated value to be looked as I typed it?
PS.
x.name loads a JSON file with some info about a person.
If i type ng-repeat="i in Tom" it will return the json, but with x.name it doesn't work.
Thanks!
EDIT (added json):
var brojVijesti = [ ];
$scope.JSONfile = brojVijesti;
// LNG Json
$http.get("/LEADERBOARDv2/jsons/LNG.php").then(function(response) {
var LNG = response.data.LNG;
$scope.LNG = LNG;
$scope.LNGbroj = LNG.length;
brojVijesti.push({"name":"LNG", "number":LNG.length});
});
// DT JSON
$http.get("/LEADERBOARDv2/jsons/DT.php").then(function (response) {
var DT = response.data.DT;
$scope.DT = DT;
$scope.DTbroj = DT.length;
brojVijesti.push({"name": "DT", "number": DT.length});
});
I believe you want i in x not i in x.name
Edit: You can then use the $parse dependency which will grab the variable of that specific name from $scope.
<div ng-repeat="x in JSONfile">
<div ng-repeat="i in x">
<span><a ng-href="{{i.link}}">{{getVariable(i.name)}}</a></span>
</div>
</div>
JS:
$scope.getVariable = function(variableName) {
//evaluate the variable name in scope's context.
return $parse(variableName)($scope);
}

How to query dom element ID with JQuery Template?

I would like to manipulate values on a JQuery template, perhaps with an inline expression or function. I am having trouble selecting the elements in order which to grab their values to perform these tasks. Here's the code:
<td class="currency">
<span id="discounted_amount">${Globalize.format(DiscountAmount, "c2")}</span>
</td>
<td class="currency">
<span id="totalAmt">${Globalize.format(InvoiceAmount, "c2")}</span>
</td>
I'm trying to basically evaluate the discounted_amount, and if there's a value, to subtract that from the totalAmt. I would like to do this on the client, without any further ajax calls. I've seen some examples of this where people have used {{if}} {{else}} {{/if}} or {{html somefunction();}}. I've just not had any success myself. Here's the function I'd like to call, or a similar structure based on whatever works best for the jquery template implementation.
function calculateDiscountedTotal() {
var discountedAmount = $('#discounted_amount').val();
var totalAmt = $('#total_amount').val();
var discountedTotal = function () {
return totalAmt - discountedAmount;
}
return discountedTotal();
}
I am unsure what template system you're using but it looks like you want the element text not the value. Value is reserved for input elements.
var discountedAmount = parseInt($('#discountered_amount').text());
function calculateDiscountedTotal() {
var discountedAmount = parseInt( $('#discounted_amount').text());
var totalAmt = parseInt($('#totalAmt').text());
var discountedTotal = function () {
return totalAmt - discountedAmount;
}
return discountedTotal();
}
console.log(calculateDiscountedTotal());
});`enter code here`

AngularJS namespace for function call in view template

I have a div with controller like this
<div ng-controller= "merchandiseListCtrl as ml">
In the js file, I have a couple of function calls and render an object on return.
vm.getlaptopTotal = (productCatergory) => getTotal(productCatergory);
var getTotal = function (_) {
var res = {
count: 0,
total: 0,
products: []
};
_.map((item) =>{
if(item.purchased){
res.count += 1;
res.total += item.price;
res.products.push(item.product);
}
});
return res;
};
So, it is obvious that I'm returning obj res with properties: count, total, and products.
In the HTML view template, I want to have to shorter namespace, shortcut to reduce the pattern ml.fn(x).products of my function call to return the properties' values for some fields. In other words, I want to assign something like ng-bind ='myTotal = ml.fn(x)', but then I run into ton of errors about $rootScope. What should I do to have a better namespace for this scenario, and complexity may go this far: funcObj.subobj.property.childproperty.grandchildproperty ? So accessibility and readibility can be accomplished?
Here is my HTML code
<div>{{ml.myTotal = ml.getlaptopTotal(ml.laptops)}}>
<!-- display the selection -->
Laptop count: {{ ml.myTotal.count }} units
<br>
<div ng-if="ml.myTotal.products">
<ul ng-repeat="product in ml.myTotal.products">
<li>{{$index+1}}) {{product}}</li>
</ul>
</div>
<br>
</div>
EDIT 1: Ran into this error because now the products array, funcObj().products is dynamic. Don't know how to fix yet. But previously, I use funcObj() as an ng-click event handler.
Thanks,

Async loading a template in a Knockout component

I'm pretty experienced with Knockout but this is my first time using components so I'm really hoping I'm missing something obvious! I'll try and simplify my use case a little to explain my issue.
I have a HTML and JS file called Index. Index.html has the data-bind for the component and Index.js has the ko.components.register call.
Index.html
<div data-bind="component: { name: CurrentComponent }"></div>
Index.js
var vm = require("SectionViewModel");
var CurrentComponent = ko.observable("section");
ko.components.register("section", {
viewModel: vm.SectionViewModel,
template: "<h3>Loading...</h3>"
});
ko.applyBindings();
I then have another HTML and JS file - Section.html and SectionViewModel.js. As you can see above, SectionViewModel is what I specify as the view model for the component.
Section.html
<div>
<span data-bind="text: Section().Name"></span>
</div>
SectionViewModel.js
var SectionViewModel = (function() {
function SectionViewModel() {
this.Section = ko.observable();
$.get("http://apiurl").done(function (data) {
this.Section(new SectionModel(data.Model)); // my data used by the view model
ko.components.get("dashboard", function() {
component.template[0] = data.View; // my html from the api
});
});
}
return SectionViewModel;
});
exports.SectionViewModel = SectionViewModel;
As part of the constructor in SectionViewModel, I make a call to my API to get all the data needed to populate my view model. This API call also returns the HTML I need to use in my template (which is basically being read from Section.html).
Obviously this constructor isn't called until I've called applyBindings, so when I get into the success handler for my API call, the template on my component is already set to my default text.
What I need to know is, is it possible for me to update this template? I've tried the following in my success handler as shown above:
ko.components.get("section", function(component) {
component.template[0] = dataFromApi.Html;
});
This does indeed replace my default text with the html returned from my API (as seen in debug tools), but this update isn't reflected in the browser.
So, basically after all that, all I'm really asking is, is there a way to update the content of your components template after binding?
I know an option to solve the above you might think of is to require the template, but I've really simplified the above and in it's full implementation, I'm not able to do this, hence why the HTML is returned by the API.
Any help greatly appreciated! I do have a working solution currently, but I really don't like the way I've had to structure the JS code to get it working so a solution to the above would be the ideal.
Thanks.
You can use a template binding inside your componente.
The normal use of the template bindign is like this:
<div data-bind="template: { name: tmplName, data: tmplData }"></div>
You can make both tmplData and tmplName observables, so you can update the bound data, and change the template. The tmplName is the id of an element whose content will be used as template. If you use this syntax you need an element with the required id, so, in your succes handler you can use something like jQuery to create a new element with the appropriate id, and then update the tmplname, so that the template content gets updated.
*THIS WILL NOT WORK:
Another option is to use the template binding in a different way:
<div data-bind="template: { nodes: tmplNodes, data: tmplData }"></div>
In this case you can supply directly the nodes to the template. I.e. make a tmplNodes observable, which is initialized with your <h3>Loading...</h3> element. And then change it to hold the nodes received from the server.
because nodesdoesn't support observables:
nodes — directly pass an array of DOM nodes to use as a template. This should be a non-observable array and note that the elements will be removed from their current parent if they have one. This option is ignored if you have also passed a nonempty value for name.
So you need to use the first option: create a new element, add it to the document DOM with a known id, and use that id as the template name. DEMO:
// Simulate service that return HTML
var dynTemplNumber = 0;
var getHtml = function() {
var deferred = $.Deferred();
var html =
'<div class="c"> \
<h3>Dynamic template ' + dynTemplNumber++ + '</h3> \
Name: <span data-bind="text: name"/> \
</div>';
setTimeout(deferred.resolve, 2000, html);
return deferred.promise();
};
var Vm = function() {
self = this;
self.tmplIdx = 0;
self.tmplName = ko.observable('tmplA');
self.tmplData = ko.observable({ name: 'Helmut', surname: 'Kaufmann'});
self.tmplNames = ko.observableArray(['tmplA','tmplB']);
self.loading = ko.observable(false);
self.createNewTemplate = function() {
// simulate AJAX call to service
self.loading(true);
getHtml().then(function(html) {
var tmplName = 'tmpl' + tmplIdx++;
var $new = $('<div>');
$new.attr('id',tmplName);
$new.html(html);
$('#tmplContainer').append($new);
self.tmplNames.push(tmplName);
self.loading(false);
self.tmplName(tmplName);
});
};
return self;
};
ko.applyBindings(Vm(), byName);
div.container { border: solid 1px black; margin: 20px 0;}
div {padding: 5px; }
.a { background-color: #FEE;}
.b { background-color: #EFE;}
.c { background-color: #EEF;}
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="byName" class="container">
Select template by name:
<select data-bind="{options: tmplNames, value: tmplName}"></select>
<input type="button" value="Add template"
data-bind="click: createNewTemplate"/>
<span data-bind="visible: loading">Loading new template...</span>
<div data-bind="template: {name: tmplName, data: tmplData}"></div>
</div>
<div id="tmplContainer" style="display:none">
<div id="tmplA">
<div class="a">
<h3>Template A</h3>
<span data-bind="text: name"></span> <span data-bind="text: surname"></span>
</div>
</div>
<div id="tmplB">
<div class="b">
<h3>Template B</h3>
Name: <span data-bind="text: name"/>
</div>
</div>
</div>
component.template[0] = $(data)[0]
I know this is old, but I found it trying to do the same, and the approcah helped me come up with this in my case, the template seems to be an element, not just raw html

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