HKQuantityTypeIdentifier initialize with string

Question

I am trying to create HKObjectType like following however all values are nill. I get enum values by string so I need to create object to get authentication.

let c = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier.init(rawValue: "bodyFatPercentage"))

let d = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier(rawValue: "BodyFatPercentage"))

let e = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier(rawValue: "bodyFatPercentage"))

Answer 1

The raw value is wrong, check this

print(HKQuantityTypeIdentifier.bodyFatPercentage.rawValue)
// HKQuantityTypeIdentifierBodyFatPercentage

so you got to write

let e = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier(rawValue: "HKQuantityTypeIdentifierBodyFatPercentage"))

But why not

let c = HKObjectType.quantityType(forIdentifier: .bodyFatPercentage)