nodeExportToCSV.js

const allVisitsStream = visitsModel
      .find()
      .populate('contact')
      .populate('helper')
      .populate('helpRequest')
      .cursor()
;

      const transformer = (doc) => {
        return {
          'VISIT STATUS': doc.status,
          'HELP REQUEST NUMBER': doc.helpRequest?.helpNumber,
          'CUSTOMER': `${doc.contact?.firstName} ${doc.contact?.lastName}`,
          'HELPER': `${doc.helper?.firstName} ${doc.helper?.lastName}`,
          'DATE': moment.utc(doc.date).format('DD-MM-YYYY'),
          'DAY OF WEEK': moment.utc(doc.date).format('dddd'),
          'START TIME': moment.utc(doc.plannedStartTime).format('HH:mm'),
          'END TIME': moment.utc(doc.plannedEndTime).format('HH:mm'),
          'DURATION': doc.duration,
          'INVOICE RATE': doc.invoiceRate,
          'INVOICE TOTAL': doc.totalCost,
          'HELPER NET': doc.helperNetPayment,
          'GLS VAT': doc.glsVAT,
          'HELPER VAT': doc.helperVAT,
          'PAYMENT METHOD': doc.contact.paymentMethod
        };
      };
    
      const csvStream = fastCsv.format({ headers: true }).transform(transformer);
      const readStream = allVisitsStream.pipe(csvStream);

      return reply.type('text/csv').send(readStream);