The little knowledge

The object.keys () method returns an array of a given Object’s own enumerable properties in the same order as the property names would be returned if the Object were iterated through normally.

What is enumerable

In plain English: you can loop through for in

Code demo

enumerable

trueThis property is only displayed if the property on the corresponding object is enumerated. The default is false

conclusion

Not all attributes can be found using a Forin loop, only enumerable attributes can be found, and non-enumerable attributes can be understood as more secure