Mine is only a suggestion, not bug

I am writing with javascript code.

I wrote the code structure Object.prototype.assign, Object.prototype.copy, Object.prototype.create codes used to create objects, such as copying or there

Why Your cycles are not using the hasOwnProperty? Because of you I have to modify the structure of the entire code.

for (var i in object)

here in your code, assing, copy, create, and face, and gives error.