Salesforce JavaScript Developer Practice Exam

The spread operator in ES6 is a versatile syntax that allows for expanding elements in arrays and properties in objects. When used in the context of objects, it effectively creates a shallow copy of the object. This means that it duplicates the properties of the original object into a new object, so they can be modified independently.

For example, using the spread operator to copy an object would look like this:

```javascript

let original = { a: 1, b: 2 };

let copy = { ...original };

```

In the above code, `copy` is a new object that has the same properties as `original`. However, if any of those properties point to another object or array, the reference to that nested structure is copied over, not the structure itself. This is what constitutes a shallow copy—while the top-level properties are duplicated, the references to nested objects remain linked to the original object.

This characteristic allows developers to operate on the new object without affecting the original, unless they manipulate the nested structures themselves.

The other choices presented do not fully encapsulate the nuances of the spread operator's functionality. The ability to merge objects without modifying the original is indeed a result of creating a shallow copy, but it’s more specific