Any speed comparison GoJS vs Lodash?

I was wondering, if you have a colllection of GoJS parts which you need to map or iterate over. Which should be (or is) faster: using GoJS collections or placing part members into normal arrays and using lodash?
Are there any metrics for these kind of use-cases?

No, but I suggest you make some jsPerf or jsBench test cases. I’d be interested in the results.

As far as collection libraries go, Ramda seems much more interesting to me. There can be a space and time performance cost to all of those libraries.

GoJS has its own collection classes because at the time there were none available that offered the basic functionality along with read-only-ness, safe iteration, and optional type-checking. Then we learned about the new Map and Set classes, so we added synonyms to the GoJS Map and Set classes to mostly match the ES5 Map and Set API.