Function key_order_cmp 

pub fn key_order_cmp(a: &str, b: &str) -> Ordering

Compare two own-property keys for OrdinaryOwnPropertyKeys enumeration order: integer-index keys sort ascending-numeric and precede all string keys; two non-index keys compare Equal so a stable sort leaves them in insertion order. (Symbols are stored as @@…/#… string keys and are non-index, so they also fall into the stable-insertion-order tail.)