How to execute Javascript code from groovy and get the results as a map?

How can I get the results of executed javascript code from groovy? I tried the following, but I always get back the string "world". I would have expected an object or map.

import javax.script.ScriptEngineManager
import javax.script.SimpleBindings

def manager = new ScriptEngineManager()
manager.getEngineByName("JavaScript").eval("""
    {hello: name}
""", [name:'world'] as SimpleBindings)

Easy!

You could map the object to a variable, and return that...

import javax.script.*

def bindings = [name:'world']

def response = new ScriptEngineManager()
    .getEngineByName('javascript')
    .eval("var r = {hello:name}; r;", bindings as SimpleBindings)

println response.hello // -> world

Or you could keep track of a response Map object, and update that...

import javax.script.*

def bindings = [name:'world',response:[:]]

new ScriptEngineManager()
    .getEngineByName('javascript')
    .eval("var r = {hello:name}; response.data = r;", bindings as SimpleBindings)

println bindings.response.data.hello // -> world

Groovy version: 2.4.5

Java version: 1.8.0_60