Setting custom Date fields using ETM

Thanks. I did try the new Date() function a couple of different ways with no luck, but this way worked.

I’ll explain why the original expression didn’t work & why @momboc’s solution worked.

acq = variables.acquiredDate;

This creates a new reference (acq) to the acquiredDate variable. Modifications of acq also affect acquiredDate & vice-versa.

ever = acq.setMonth(acq.getMonth() + 49);

 adds 49 months to acq/acquiredDate and sets ever to the timestamp (milli seconds since 1st Jan 1970). See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/setMonth  - specifically see “Return Value”.

ever;

Sets the custom fields to the number of millis since 1/1/1970)

Using new Date()  with the result of setMonth() solves the problem by creating a new Date object for the custom field value.

A simpler solution would be 

variables.acquiredDate.setMonth(variables.acquiredDate.getMonth() + 49);

variables.acquiredDate;

this makes it clear that setMonth() is modifying the acquiredDate and not just a copy.,

Alternatively:

var acq= new Date(variables.acquiredDate);

acq.setMonth(acq.getMonth() + 49);

acq;

Creates a copy of acquiredDate before modification. In this case acquiredDate isn’t changed. This could be important if subsequent mappings reference acquiredDate, and expect the original value - not the one 4 years later.