I've started learning Knockout and I'm having some trouble filtering an observable array on a button click and displaying the results.
This is my model:
function Product(data) {
this.id = data.id;
this.name = data.name;
this.price = data.price;
this.description = data.desc;
this.image = data.image;
this.genre = data.genre;
this.show = data.show;
this.offer_desc = data.offer_desc;
this.offer_id = data.offer_id;
}
function ProductModel() {
var self = this;
self.products = ko.observableArray([]);
$.getJSON('../PHP/Utilities.php?json=true', function(json) {
var mappedProducts = $.map(json, function(item) { return new Product(item) });
self.products(mappedProducts);
});
self.filterProducts = ko.computed(function(genre) {
if(typeof genre === 'undefined') {
return self.products(); //initial load when no genre filter is specified
} else {
return ko.utils.arrayFilter(self.products(), function(prod) {
return prod.genre = genre;
});
}
});
}
ko.applyBindings(new ProductModel());
This is the html:
<div data-bind="foreach: filterProducts">
<div class="row">
<div class="col-md-2">
<img data-bind="attr:{src: '../images/' + image, alt: name}" />
</div>
<div class="col-md-2" data-bind="text: name"></div>
<div class="col-md-1" data-bind="text: price"></div>
<div class="col-md-3" data-bind="text: description"></div>
<div class="col-md-1" data-bind='text: offer_id'>
<div class="col-md-2" data-bind="text: genre"></div>
<div class="col-md-1" data-bind="text: show"></div>
</div>
</div>
I'm also not sure how to bind a click function to filter the products on genre. I thought something like this...but it doesn't work
<button data-bind="click: filter('1')"> Filter </button>
self.filter = function(genre) {
self.filterProducts(genre);
}
You cannot have a function with parameters inside a ko.computed
.
What you need is store the current filter in a new property and use that in your computed
function ProductModel() {
var self = this;
self.products = ko.observableArray([]);
self.currentFilter = ko.observable(); // property to store the filter
//...
self.filterProducts = ko.computed(function() {
if(!self.currentFilter()) {
return self.products();
} else {
return ko.utils.arrayFilter(self.products(), function(prod) {
return prod.genre == self.currentFilter();
});
}
});
}
And in your click
handler just set the current filter:
<button data-bind="click: function() { filter('1') }"> Filter </button>
self.filter = function(genre) {
self.currentFilter(genre);
}
Demo JSFiddle
Note the function() { }
in needed if you want to pass additional arguments a in click
binding (see also in the documentation), otherwise Knockout would execute your function when it parses the binding and not when you click on the button.