Handling FHIR without getting burned

4:32 - Use FHIRModels with Health Records FHIR data from HealthKit

// Use with Health Records FHIR data from HealthKit
import HealthKit
import ModelsDSTU2

// Grab HKClinicalRecord from HealthKit API
let clinicalRecord: HKClinicalRecord
let resource = clinicalRecord.fhirResource!

// Print the prescription note
let decoder = JSONDecoder()
let prescription = try decoder.decode(MedicationOrder.self, from: resource.data)
print("\(prescription.note)")

5:04 - Use FHIRModels with Health Records FHIR data from HealthKit, part 2

// Make using "TimingRepeat" period dates easier by writing an extension
extension TimingRepeat {
    var periodDisplayString: String? {
        if case .period(let period) = bounds {
            return "\(period.start) - \(period.end)"
        }
        return nil
    }
}

// Collect all dosage instructions on medication prescriptions
let instructions: [String] = prescription.dosageInstruction?.map { dosage in
    guard let period = dosage.timing?.repeat?.periodDisplayString else {
        return "\(dosage.text)"
    }
    return "\(period): \(dosage.text)"
}

6:20 - Supporting multiple FHIR releases

// Supporting multiple releases
import ModelsDSTU2
import ModelsR4

let decoder = JSONDecoder()
let release: FHIRRelease
let data: Data

let note: String? = nil
switch release {
case .dstu2:
    let model = try decoder.decode(ModelsDSTU2.MedicationOrder.self, from: data)
    note = model.note?.value?.string
case .r4:
    let model = try decoder.decode(ModelsR4.MedicationRequest.self, from: data)
    note = model.note?.compactMap({ $0.text.value?.string }).joined(separator: "\n")
default:
    note = "Unsupported FHIR release \(release)"
}