Recursive flatten

Hi,

Is it possible to retrieve a flattened list of nodes recursively for a tree of arbitrary depth? I know that the flatten operator isn't recursive, but is there some other pattern that can be used?

So for this data:

```
{
"node": {
"label": "root node",
"nodes": [
{
"label": "node 1",
"nodes": [
{
"label": "node 1:1"
},
{
"label": "node 1:2"
}
]
},
{
"label": "node 2",
"nodes": [
{
"label": "node 2:1"
},
{
"label": "node 2:2"
}
]
}
]
}
}
```

I could get:

```
[
{
"label": "root node"
},
{
"label": "node 1"
},
{
"label": "node 1:1"
},
{
"label": "node 1:2"
},
{
"label": "node 2"
},
{
"label": "node 2:1"
},
{
"label": "node 2:2"
}
]
```