gistfile1.txt

type
    jsobj {.importc.} = object
        update*: proc(){.nimcall.}

    d3_obj {.importc.} = object
        linear* : proc(): jsobj{.nimcall.}

# this might work, to make it callable, i doubt it though
proc `()` (obj:jsobj; scale:float): float {.importc.}


var d3test {.importc,nodecl.}: d3_obj
var s = d3test.linear()
s.update()