A property descriptor must have keys "enumerable" and "configurable"

[zhirzh]

TypeScript Version: 3.7.2

Expected behavior: In a property descriptor object, keys configurable and enumerable should not be optional.

Actual behavior: These properties are marked as optional (see here and here).

[IllusionMH]

Why they should be required?
MDM mentions them as optional https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty#Description

According to latest draft of spec (and previous versions) https://tc39.es/ecma262/#sec-topropertydescriptor explicitly check if these keys are in descriptor object without throwing if they are not available.

[zhirzh]

Yes, you are right on that. I was only comparing the result of Object.getOwnPropertyDescriptor() and concluded that keys configurable and enumerable must be present.

[RyanCavanaugh]

The return type of Object.getOwnPropertyDescriptor could be more precise by making these non-optional since they're always returned