Is there any way to save my expression in a calculation field or data event when it is not valid?

In the event that you have an invalid javascript/expressions in the calculation field, but would like to save the work you have done, you can comment out the code that is invalid. This will allow you to save the work that has been done with out impacting your app.

To do this, you need to add /*  before the code and */  after the code.

Example: