This works then in this release at least:
fun getProperties(any: Any): MutableMap<String, Any> {
val objectKeys = js("Object.keys")
val keys: dynamic = objectKeys(any)
val obj: dynamic = any
val map = mutableMapOf<String, Any>()
for (i in 0..keys.length - 1) {
val key = keys[i]
map.put(key, obj[key])
}
return map
}