Date variable (SuiteScript)

When I'm creating a new date variable

Var ExpectedDate = new date (date1)

I'm seeing the following into the debug log:

Error {"message":"Error","details":"date is not defined"}
Debug {"message":"date1 after format = 16/7/2021"}
Debug {"message":"date1 before format = Fri Jul 16 2021 00:00:00 GMT+0200 (Midden-Europese zomertijd)"}

There is a date/time pulled out of a record which is formatted into a date. When I want to use the new date I get the message "Date is not defined".

The whole script:

// Order date van de salesorder ophalen
var date1 = currentRec.getValue({fieldId: 'trandate'});
log.debug({message:'date1 before format = '+date1})
date1 = format.format({
	value: date1,
	type: format.Type.DATE
});
log.debug({message:'date1 after format = '+date1})


// Lead time in days van de itemrecord ophalen
var leadTime = itemRec.getValue({
	fieldId: 'leadtime'
});
var expectedDate = new date(date1);
expectedDate.setDate(expectedDate.getDate() + leadTime);
log.debug({message:'expected date = '+expectedDate});