A method to aggregate and group unplanned vaccinations

vaccineMethod.ts

interface VaccineDose {
  name: string;
  category: string;
  doseNumber: number;
  vaccinationDate: Date;
  isPlanned: boolean;
}

interface VaccineAggregate {
  category: string;
  lastDose: number;
  count: number;
}

/**
 * Group unplanned patient vaccinations by category (TBE/Measles etc)
 */
export function aggregateVaccines(doses: VaccineDose[]): VaccineAggregate[] {
  const pastDoses = doses.filter((dose) => !dose.isPlanned);
  const reducedMap = new Map<string, VaccineAggregate>();

  pastDoses.forEach((dose) => {
    const accumulatedData = reducedMap.get(dose.category);
    if (accumulatedData) {
      reducedMap.set(dose.category, {
        category: dose.category,
        lastDose:
          accumulatedData.lastDose > dose.doseNumber
            ? accumulatedData.lastDose
            : dose.doseNumber,
        count: accumulatedData.count + 1,
      });
    } else {
      reducedMap.set(dose.category, {
        category: dose.category,
        lastDose: dose.doseNumber,
        count: 1,
      });
    }
  });

  return Array.from(reducedMap.entries()).map(([k, v]) => {
    return v;
  });
}