indexOF method in a Javascript array

Question

I have the following list constructed:

var names_Array= []; 
var names_List= new WinJS.Binding.List(names_Array);
names_List.push({ name: "Joe Dowling", image: "image/Joe Dowling.png", ClientID: "1234" }, { name: "Esteban Flamenco ", image: "image/Esteban Flamenco.png", ClientID: "6666" });

I want to be able to get the index of the list where the ID is 6666. My attempt thus far was to do the following:

var number = names_List.indexOf('{ name: "Esteban Flamenco ", image: "image/Esteban Flamenco.png", ClientID: "6666" }');
console.log(number);

But I am getting -1 (i.e. not found). Where am I going wrong?

@user2363025 no, using an object literal there won't work either. You have to write a simple loop to search for your object by property value. Also that's not a JSON list; it's a JavaScript array. — Pointy
– Pointy, Commented Jun 17, 2013 at 13:35
@Pointy could you give me a basic skeletal framework of what you're describing or point me to a site that can have them — user2363025
– user2363025, Commented Jun 17, 2013 at 13:36

Pointy · Accepted Answer · 2013-06-17 14:54:11Z

2

You have to create a search facility tailored to your needs, perhaps like this:

function findObject( list, property, value ) {
  var i;
  for (i = 0; i < list.length; ++i)
    if (list[i] != null && list[i][property] == value)
      return elem;
}

Then you can do this:

var client6666 = findObject(names_List, 'ClientID', '6666');

If a matching element can't be found, the return value is undefined.

edit — I don't know much (well, anything) about the WinJS APIs, but it looks like those "List" objects aren't just simple arrays. I think you may have to do something like this (no guarantees as I can't test this):

function findObject( list, property, value ) {
  var i, elem;
  for (i = 0; i < list.length; ++i)
    elem = list.getAt(i);
    if (elem != null && elem[property] == value)
      return list[i];
}

edited Jun 17, 2013 at 14:54

answered Jun 17, 2013 at 13:42

Pointy

415k62 gold badges600 silver badges631 bronze badges

Sign up to request clarification or add additional context in comments.

10 Comments

Katana314 Over a year ago

This may need to be extended so it can apply to entire-object matches. Right now, the OP's example seems to intend to compare all values for matching (of course, functionally, I think it should just be the ID, as you've done it, so I voted you up). Oh, and just from my personal preference: An alternative way of checking "if (list[i] != null)" is "if (i in list)"

Ian Over a year ago

Yeah I don't think list[i] != null would work at all...if anything, compare to undefined, or typeof x !== "undefined". I can't see a reason why list[i] would be null, unless there's something special about WinJS.Binding.List

user2363025 Over a year ago

@Pointy Sincere thanks for the help. I keep getting undefined

user2363025 Over a year ago

@Katana314 I tried using if (i in list) also but I'm still getting undefined

user2363025 Over a year ago

@ Ian I tried comparing it to undefined and typeof x !== "undefined" but I'm still getting undefined. any idea why?

|

Collectives™ on Stack Overflow

indexOF method in a Javascript array

1 Answer 1

10 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

10 Comments

Your Answer

Sign up or log in

Post as a guest

Related