For the record about not implemented js functions:

List.flatten is not a function

List.binarysearch is not a function

I wrote Fantom code to do the work instead of using this functions, but still hope to see them implemented.

List.makeObj is not a function

Here's more interesting case, because the first attempt to workaround failed:

list := List.make(Obj?#, n)
n.times { list.add(it) } // leads to "Cannot find function splice"

And only this worked:

list := Obj?[,]
list.capacity = n
n.times { list.add(it) }

Promoted to ticket #1385 and assigned to andy

Ticket resolved in 1.0.62

All these seems to have gotten fixed over the last year or so - everything works now.