# New nodes from split are clones or existing ones
**URL:** https://discuss.prosemirror.net/t/new-nodes-from-split-are-clones-or-existing-ones/4616
**Category:** Uncategorized
**Created:** [May 16, 2022, 5:11pm UTC](https://discuss.prosemirror.net/t/new-nodes-from-split-are-clones-or-existing-ones/4616 "2022-05-16T17:11:49Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@jeromebeam](https://discuss.prosemirror.net/u/jeromebeam)
#### Post date: [May 16, 2022, 5:11pm UTC](https://discuss.prosemirror.net/t/new-nodes-from-split-are-clones-or-existing-ones/4616/1 "2022-05-16T17:11:49Z")
I defined a schema which is almost the same as prosemirror’s schema-list :
```auto
- note
- children (ul)
- bullet+ (li)
- paragraph children?
```
where `paragraph` (p) is `inline*`
To split bullets/paragraph I also have reused the `splitListItem` from the list-schema package. However I also need to assign a new unique ID to every new bullet node that is created by the split.
The split works but new nodes are created as node copies: `transform.split()` does a `node.copy()` which copies also the ID of the cloned node. I saw a `descendants()` technique to scan nodes for one without ID (and so assign a new one) but is is useless as soon as a cloned already have an ID (unless we try to detect two equals IDs).
Isn’t there another technique to initialize a new node? `transform.split()` is able to invoke `NodeType.create()` but I never get the required `typeAfter` to do so.
---
### Author:  [@marijn](https://discuss.prosemirror.net/u/marijn)
#### Post date: [May 17, 2022, 6:06am UTC](https://discuss.prosemirror.net/t/new-nodes-from-split-are-clones-or-existing-ones/4616/2 "2022-05-17T06:06:12Z")
You can’t, as a rule, maintain unique IDs at the transform/step level, but what people tend to do here is register a plugin with an `appendTransaction` hook that checks and, if necessary, updates the document to enforce unique IDs whenever new ID-bearning nodes are created.
---
### Author:  [@jeromebeam](https://discuss.prosemirror.net/u/jeromebeam)
#### Post date: [May 17, 2022, 6:32am UTC](https://discuss.prosemirror.net/t/new-nodes-from-split-are-clones-or-existing-ones/4616/3 "2022-05-17T06:32:22Z")
Yes I saw the plugin technique, described as the « `descendants()` » in my initial post. However this technique detects new nodes when they miss some attribute (id) to initialize, whereas nodes created through `copy` _already have that field_ cloned from the previous node.
---
### Author:  [@tslocke](https://discuss.prosemirror.net/u/tslocke)
#### Post date: [May 22, 2022, 12:10pm UTC](https://discuss.prosemirror.net/t/new-nodes-from-split-are-clones-or-existing-ones/4616/4 "2022-05-22T12:10:28Z")
> nodes created through copy already have that field cloned from the previous node.
Right. I have a uniqueIDs plugin and it does have to deal with this issue, which complicates the code significantly. I’ve seen a bunch of example code posted that ignores this. I would share but the plugin is doing a couple of other things so it’s not a good example of how to achieve just this.
Essentially I have to scan the document for duplicates. I avoid having to do a deep scan of the entire node tree by keeping track of the entire set of nested IDs on each node. You can do this either a hacky way, by adding a new property to the node (which are supposed to be immutable), or a clean way, using a WeakMap.
---
### Author:  [@jeromebeam](https://discuss.prosemirror.net/u/jeromebeam)
#### Post date: [May 22, 2022, 2:49pm UTC](https://discuss.prosemirror.net/t/new-nodes-from-split-are-clones-or-existing-ones/4616/5 "2022-05-22T14:49:10Z")
Yes @tslocke that’s what I did: when using `descendants` I initialize a set of “know ids” and look for duplicates: I then assume the latest duplicate is the new id. That’s kind of frustrating (and a bit scary for performance if you have a big doc) when you know that there is a `create()` method on your NodeType (which can be called by the split, but only when splitting at Node’s edge apparently, and I don’t understand why yet).