getSafeProperty fails when object is an instance of a class.

[krishnanelloore-gep]

In the getSafeProperty function, the first step is to make sure the object is a plain object by calling isPlainObject, and in this function the code is object.constructor===Object. Here is where our code breaks.

[josdejong]

The scope of mathjs expressions does only support plain objects or Map, but not classes. These restrictions are in place to limit security risks.