If you want to change the date format in suitescript the following sample will be used.
First load the N/format module
Then pass your date field into Date function like
let dateField=new Date(lastDonateDate);
Then assign your date format into a varaible,
let myDateFormat=’M/D/YYYY’
Then use format.parse to change the date format
let formattedDate = format.parse({
value: dateField,
type: format.Type.DATE,
format: myDateFormat
});