Given two Arrays - contacts() & contactsSelected() - How to match the two?

I have two arrays (contacts & contactsSelected) both with the following type of structure:

{
    id: 1,
    name: bob
},
{
    id: 213,
    name: Rob
}

I'm using KnockoutJS. How Can I iterate over contacts() and for each row, determine if that row's ID is contained in the contactsSelected array? In KnockoutJS I have something like this:

userCardModel.contactsToShow = ko.dependentObservable(function () {      

        return ko.utils.arrayFilter(this.contacts(), function(contact) {
            return /////////////// LOGIC GOES HERE TO See if this contact.id() is contained开发者_如何学编程 in the contactsSelected() array
        });


}, userCardModel);

Thanks

---

OK, you could do it like so...

var contactsSelectedLength = contacts.length;

for (var i = 0, contactsLength = contacts.length; i++) {
   var contact = contacts[i];
   for (var j = 0; j < contactsSelectedLength; j++) {
       var selectedContact = contactsSelected[j];
       if (contact.id == selectedContact.id) {
          // It is in there!
       }
   }
}

---

Add the IDs of "contactsSelected" as properties of an object so they can be accessed in better-than-linear time using the "in" operator or "hasOwnProperty" method:

var getSelectedIds = function(sel) {
  var len=sel.length, o={}, i;
  for (i=0; i<len; i++) {
    o[sel[i].id] = true;
  }
  return o;
};
var selectedIds = getSelectedIds(contactsSelected);
(1 in selectedIds); // => true
(2 in selectedIds); // => false
selectedIds.hasOwnProperty(213); // => true
selectedIds.hasOwnProperty(214); // => false