knockout-collection

A knockout observable array as hashmap

usage

var item1 = {
  id: ko.observable(1),
  label: 'Item 1'
};
 
var item2 = {
  id: ko.observable(2),
  label: 'Item 2'
}
 
var collection = new KnockoutCollection([item1], { key: 'id' });
 
expect(collection.get(2)).to.be.undefined;
 
collection.add(item2);
 
expect(collection.get(2)).to.have.property('label', 'Item 2');
 
collection.remove(item1);
collection.remove(item2);
 
expect(collection.toArray()).to.have.length(0);

api

If you need direct access to the underlying ko.observableArray you can use collection.items. Use this only to bind, not to modify.

construction

You can pass an array as items.

new KnockoutCollection(['my', 'array', 'items']);

If you want to manage an ko.observableArray you can pass it as items and set the option: reference:

var items = ko.observableArray([item1, item2]);
var collection = new KnockoutCollection(items, { key: 'id', reference: true });
 
collection.remove(item1);
 
// items() will be [item2]

.add(item)

adds an item to the collection which is identified by the value of the (observable-)property with name options.key.
The item is only added, if it isn't already contained in the collection

.remove(item)

removes the item from the collection. If it isnt available in the collection nothing is done

.get(keyValue)

returns the item with the value of the (observable-)property with name options.key equal to keyValue.
it will return undefined if the collection does not contain the item.

.contains(item)

checks if the item is contained in the collection.

.length

You can use the length property as you would use it for an array:

var collection = new KnockoutCollection(['i1', 'i2']);
 
console.log(collection.length === 2); // is true

.removeAll()

Removes all items from the collection