Calculated Values - Setting current date

I have 3 Timestamp fields that needs to set to current date based on the 3 values (1,2,3) selection in a enumerated field.
For example-
When i select 1 the first date field should be set to current date.
When i select 2 the second date field should be set to current date (Without losing the value for first field)
When i select 3 the third date field should be set to current date. (Without losing the value for first or second field)

Now the problem is when i select 1 the first date field gets set to current date which is as expected. When i select 2 the second date field gets set to current date but here I also lose the value for the first date field which was set when i selected 1. same thing happens when i select 3.

Any advice on how can achieve this without losing any values ?

Below is the script i am using-



dojo.provide("com.example.script.CurrDateForOne");
dojo.require("dojo.date"); // We need the date class from Dojo to compare two dates
dojo.require("dojo.date.stamp"); // We need the stamp class to work with ISO date strings

(function() {
    dojo.declare("com.example.script.CurrDateForOne", null, {

        getValue: function(attribute, workItem, configuration) {
           
            //get the current date
            var date=new Date();
            var currDate=dojo.date.stamp.toISOString(date, {milliseconds:true, zulu:true});
            console.log("Date: "+currDate);
           
                         
           
            //get the current status
            var status=workItem.getValue("com.example.team.workitem.fdreviewStatus");
            console.log("Status: "+status);
           
           
            if(status === "com.example.team.workitem.enum.ReviewStatus.literal.l3"){               
                return currDate ;
            }
        }
    });
})();