lib_index.js

var addon = require('../native');

console.log(addon.test({ foo: ["bar"] }));

native_src_lib.rs

#[macro_use]
extern crate neon;

use neon::vm::{Call, JsResult};
use neon::js::{JsObject, JsValue, Object};

fn test(call: Call) -> JsResult<JsValue> {
    let scope = call.scope;
    let arg = try!(call.arguments.require(scope, 0));
    let obj = try!(arg.check::<JsObject>());
    let foo = try!(obj.get(scope, "foo"));
    let obj = try!(foo.check::<JsObject>());
    obj.get(scope, 0)
}

register_module!(m, {
    m.export("test", test)
});