Question

How do I find the last element in a JavaScript object, if by “last” I consider the one with the largest index? I.e. I am receiving an object similar to an array over ajax (as json), but it also has a non-numeric key:

var received = {
   0: 'something',
   1: 'something else',
   2: 'some stuff',
   3: 'some more stuff',
   'crap' : 'this screws the whole thing'
}

If it were a plain array, I would use array.length. Similarly, I can simply iterate element by element to find it.

Is there a better way? If jQuery is needed for the solution, that’s also fine.

Answer 1

This works like the codes from zzzzBov and David Müller, but uses library functions do make it much shorter:

Math.max.apply(null, Object.keys(test).filter(isFinite)) // 3

If you have objects with enumerably-extended prototype objects (which is not the case for JSON.parse results) you might want to use Object.getOwnPropertyNames instead.