Updating Knockout.js Observable array element value

Question

I need to update an observable array element value. The observable array is a collection of class objects. First I need to find out matching object by id and update some other property values of the object.

var Seat = function(no, booked) {     var self = this;     self.No = ko.observable(no);     self.Booked = ko.observable(!!booked);      // Subscribe to the "Booked" property     self.Booked.subscribe(function() {         alert( self.No() );     }); };  var viewModel = {     seats: ko.observableArray( [         new Seat(1, false), new Seat(2, true), new Seat(3, true),         new Seat(4, false), new Seat(5, true), new Seat(6, true),         new Seat(7, false), new Seat(8, true), new Seat(9, true)     ] ) }; 

Can anyone suggest the approach of updating the view model? Let's say I want to update booked value to "false" for the seat no 2.

http://jsfiddle.net/2NMJX/3/

Answer 1

That's pretty simple with knockout:

// We're looking for the Seat with this No  var targetNo = 2;  // Search for the seat -> arrayFirst iterates over the array and returns the // first item that is a match (= callback returns "true")! var seat = ko.utils.arrayFirst(this.seats(), function(currentSeat) {     return currentSeat.No() == targetNo; // <-- is this the desired seat? });  // Seat found? if (seat) {     // Update the "Booked" property of this seat!     seat.Booked(true); } 

http://jsfiddle.net/2NMJX/4/