HKSampleQuery returns an array of AnyObject as a result. Now, I'm almost guaranteed that it will be an array of HKQuantitySample objects. I would like to end up with a list of NSDate objects for dates I already have Health sample data for that. I figure I can filter the results array to only include HKQuantitySample objects and then map them to …

gistfile1.swift

import HealthKit

let quantityType = HKObjectType.quantityTypeForIdentifier(HKQuantityTypeIdentifierBodyMass)
let query = HKSampleQuery(sampleType:quantityType, predicate:nil, limit:0, sortDescriptors:nil) {
    query, results, error in

    // results is [AnyObject]

    let samples = results.filter { 
        ($0 as? HKQuantitySample) != nil
    }
	
    // samples is [AnyObject]
	
    // I need the cast here because the filter hasn't changed the type of the array
    // Ideally samples would be [HKQuantitySample] going into this function
    let dates = samples.map {
        ($0 as HKQuantitySample).startDate
    }
    
    // dates is [NSDate!]
}

// The result is that dates is the array [NSDate!] which then causes issues down the line :-/