Cannot assign to 'this'
the object currently executing a method,
the global object if there is no current method (or the method does not belong to any other object).
Inside a method, you can use this to refer to the current object, but you cannot assign a new value to this.
To correct this error
Do not attempt to assign to this. To access a property or method of an instantiated object, use the dot operator (e.g., circle.radius).