collapse/expand nested nodes?

[yifanwu]

I'm submitting a...

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report  
[ ] Performance issue
[x] Feature request
[ ] Documentation issue or request
[ ] Other... Please describe:

Current behavior

Currently one could specify nested nodes, but there is not way to "collapse" the nested nodes into a smaller summary node

Expected behavior

Add an API that allows a nested set of nodes to be collapsed/expanded---so here the 2>2.1 and 2>2.2 nodes will be gone, replaced by some "summary node" (whose color/edge style is a little different to indicate interactivity, which we can configure through the component props/css definition).

I think this can be "hacked" together right now by modifying the node specification---update the state and omit/add the nested nodes, but might make the layout funky? Let me know if you think this is actually a proper way to use the library.

What is the motivation / use case for changing the behavior?

I think this is a pretty important feature for visualization---"summary first, detail on demand". At least true for our project!

[amcdnl]

Yes, I think this would be a great feature. It could be implemented today but just redacting certain nodes from your model and some custom button on a node though I would like to make it easier to do.

The reason I haven't done it yet is because it gets a little tricky in branching scenarios - take the following ( my app ):

If you collapse Approve by Email, would the Send Email also be hidden since it would have uncollapse parent?

If you want to take a stab at it, I would recommend looking at this library - it can help you determine children/parents easily to figure out what nodes to remove: https://www.npmjs.com/package/dependency-graph

[yifanwu]

Interesting! I was more thinking about supporting collapse just for the already nested nodes, like the screenshot I have above. That way the collapsing logic is clear---just shrinking the box of the nested group, that way it's purely visual than semantic.

[amcdnl]

Ah I see - ya I was thinking of it in a different way.

The approach of trimming the graph would still work ( and be easier ).

I'll try to add an example of that for you but I'm interested in solving this other more generic collapsing too.