I'm trying to create a REST GET endpoint to return a list of employees in our environment.

var res = search.create({type: search.Type.EMPLOYEE, filters:[ ["firstname", <http://search.Operator.IS|search.Operator.IS>, "Chase"]], columns: ['department']}).run();
res.getRange({start: 0, end: 1000}).forEach(function(emp_srec) {
    var employee = record.load({type: record.Type.EMPLOYEE, id: emp_srec.id});
});

That's more or less what I'm attempting to do. The search object doesn't return all of the fields. Some fields can't be added to the columns, so load their actual record. Add each record to a result set and provide that array of records as the resultant JSON.