in src/main/java/org/apache/sling/scripting/sightly/js/impl/rhino/HybridObject.java [60:69]
public Set<String> getPropertyNames() {
Object[] properties = scriptable.getIds();
Set<String> keys = new HashSet<String>();
for (Object property: properties) {
if (property instanceof String) {
keys.add((String) property);
}
}
return keys;
}