How do I know how many items an object literal contains?

Question

For example, how do I know that the myObject object literal contains two items?

var myObject = {
  item1 : "blablabla",
  item2 : "blablabla
};

Duplicate: http://stackoverflow.com/questions/1345939/how-do-i-count-javascript-objects-attributes (see haim evgi's answer) — kennytm, Jan 17 '10 at 07:36

score 2 · Answer 1 · edited May 23 '17 at 12:19

2

edited May 23 '17 at 12:19

Community

answered Jan 17 '10 at 07:33

Haim Evgi

kennytm · Answer 2 · 2010-01-17T07:45:12.267

0

If you didn't override the prototypes of myObject,

var count = 0;
for (var k in myObject) ++ count;
return count;

Otherwise, see the answer haim's link.

edited Jan 17 '10 at 07:45

answered Jan 17 '10 at 07:32

kennytm

What about properties inherited from the prototype chain? – Zack The Human Jan 17 '10 at 07:41
1

The `for...in` statement iterates also properties that are up in the prototype chain, I would suggest you to check if the property exists *physically* in the object by `myObject.hasOwnProperty(k);` or `Object.prototype.hasOwnProperty.call(myObject, k);` for the paranoid :) – Christian C. Salvadó Jan 17 '10 at 07:43
I blame Douglas Crockford and JSLint. – Zack The Human Jan 17 '10 at 08:59

score 0 · Answer 3 · answered Jan 17 '10 at 07:34

0

var n = 0
for (var i in o) ++n
alert(n)

answered Jan 17 '10 at 07:34

jspcal

3 Answers3