Object. assign does not copy prototype properties and methods. This method does not create a deep copy of Source Object, it makes a shallow copy of the data. For the properties containing reference or complex data, the reference is copied to the destination object, instead of creating a separate object.

Is spread operator deep copy?

The spread operator makes deep copies of data if the data is not nested. When you have nested data in an array or object the spread operator will create a deep copy of the top most data and a shallow copy of the nested data.

How do you deep copy an object?

Using the spread syntax or Object. assign() is a standard way of copying an object in JavaScript. Both methdologies can be equivalently used to copy the enumerable properties of an object to another object, with the spread syntax being the shorter of the two.