10.1.11.1 OrdinaryOwnPropertyKeys ( O )
The abstract operation OrdinaryOwnPropertyKeys takes argument O (an Object) and returns a List of property keys. It performs the following steps when called:
1. Let keys be a new empty List.
2. For each own property key P of O such that P is an array index, in ascending numeric index order, do
a. Append P to keys.
3. For each own property key P of O such that P is a String and P is not an array index, in ascending chronological order of property creation, do
a. Append P to keys.
4. For each own property key P of O such that P is a Symbol, in ascending chronological order of property creation, do
a. Append P to keys.
5. 5. Return keys.