Is it possible for a JavaScript array to contain itself?

Question

In Ruby, it's possible for an array to contain itself, making it a recursive array. Is it possible to put a JavaScript array inside itself as well?

var arr = new Array();
arr[0] = "The next element of this array is the array itself."

Now how can I move arr into arr[1] so that the array contains itself recursively, (e. g., so that arr[1] is arr, arr[1][1] contains arr, arr[1][1][1] contains arr, etc.)?

You can do it, but it will cause JSON.stringify to throw errors if you need to send it to a remote machine. — Paul, May 22 '13 at 02:53

score 16 · Accepted Answer · answered May 21 '13 at 19:53

16

Sure:

var a = [1];
a.push(a);

They're the same object:

a[1] === a[1][1]  // true

And a convincing screenshot:

enter image description here

answered May 21 '13 at 19:53

Blender

289,723
53
439
496

Which desktop application or web application did that screenshot come from? – Anderson Green May 21 '13 at 19:55
1

Since `a[1] === a[1][1] === a[1][1][1]` is actually false, it might make more sense to show it on two lines: `a[1] === a[1][1] // true` and `a[1] === a[1][1][1] // true` – Paul May 21 '13 at 19:55
1

@AndersonGreen That looks like a screenshot of Chrome's console. – Paul May 21 '13 at 19:56
1

@AndersonGreen seems like Google Developer Tools ) – Kirill Ivlev May 21 '13 at 19:56
@Paulpro: Thanks. Sometimes you forget that JavaScript isn't Python. – Blender May 21 '13 at 19:58
1

@AndersonGreen Looks like the console from Developer tools (F12) in Chrome Browser. – Vitor Canova May 21 '13 at 19:58
@AndersonGreen - Sounds like it's time for you to learn how to use a debugger... I don't know how you can survive for an instant without one! – jahroy May 22 '13 at 02:55
I think I just headsploded. – Asad Saeeduddin Jun 05 '13 at 19:39

score 11 · Answer 2 · answered May 21 '13 at 19:53

11

Yes, sure:

var x = [];
x.push(x);
console.log(x[0] === x); // true

answered May 21 '13 at 19:53

phihag

278,196
72
453
469

Is it possible for a JavaScript array to contain itself?

2 Answers2

Linked