FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
refer to https://github.com/zloirock/core-js/issues/389#issuecomment-378444109 get description

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
refer to https://github.com/zloirock/core-js/issues/389#issuecomment-378444109 get description

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
any key should propertyIsEnumerable = true
ACTUAL -
short integer-string key will report as false

REPRODUCIBILITY :
This bug can be reproduced always.