# How to track dependencies between nodes

**URL:** <https://discourse.nodered.org/t/how-to-track-dependencies-between-nodes/72393>\
**Category:** Developing Nodes\
**Tags:** flexdash\
**Created:** [18 December 2022 21:39 UTC](https://discourse.nodered.org/t/how-to-track-dependencies-between-nodes/72393 "2022-12-18T21:39:53Z")\
**Posts on this page:** 1\
**Showing post:** 6

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**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [19 December 2022 01:01 UTC](https://discourse.nodered.org/t/how-to-track-dependencies-between-nodes/72393/6 "2022-12-19T01:01:22Z")

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> [@tve](#):
>
> Good point. What are the semantics of nodes:remove?

```auto
    RED.events.on('nodes:remove', function(node) {
        if ( node.type === 'uibuilder') {
            mylog('>> nodes:remove >>', node)
            delete editorInstances[node.id]
        }
    })

```

🙂

> [@tve](#):
>
> Specifically, if I get that callback am I guaranteed that I will never see its node ID again (except for random collision)? If not, then how does it help?

I _think_ the id's are UUID's? So they should be pretty unique, at least within a specific flow file. I don't know for sure though.

> [@tve](#):
>
> Also, if someone imports a flow or opens a flow and it contains a Node ID and RED.nodes.node(id) returns null, what can I conclude about it?

When you import, if there is a clash, I think that node-red sorts out the ID's. [In which situations would Node IDs change ? Import or any other as well? - General - Node-RED Forum (nodered.org)](https://discourse.nodered.org/t/in-which-situations-would-node-ids-change-import-or-any-other-as-well/65500)

Sounds like some testing is in order! 🙂

[RED.events : Node-RED (nodered.org)](https://nodered.org/docs/api/ui/events/#methods-on)

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