created new Methods_Characteristic category to handle HealthKit Characteristic...

created new Methods_Characteristic category to handle HealthKit Characteristic methods and implemented getters for sex and dob

RCTAppleHealthKit/RCTAppleHealthKit+Methods_Characteristic.h

+//
+//  RCTAppleHealthKit+Methods_Characteristic.h
+//  RCTAppleHealthKit
+//
+//  Created by Greg Wilson on 2016-06-29.
+//  Copyright © 2016 Greg Wilson. All rights reserved.
+//
+
+#import "RCTAppleHealthKit.h"
+
+@interface RCTAppleHealthKit (Methods_Characteristic)
+
+- (void)characteristic_getBiologicalSex:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
+- (void)characteristic_getDateOfBirth:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback;
+
+@end

RCTAppleHealthKit/RCTAppleHealthKit+Methods_Characteristic.m

+//
+//  RCTAppleHealthKit+Methods_Characteristic.m
+//  RCTAppleHealthKit
+//
+//  Created by Greg Wilson on 2016-06-29.
+//  Copyright © 2016 Greg Wilson. All rights reserved.
+//
+
+#import "RCTAppleHealthKit+Methods_Characteristic.h"
+#import "RCTAppleHealthKit+Utils.h"
+
+@implementation RCTAppleHealthKit (Methods_Characteristic)
+
+
+- (void)characteristic_getBiologicalSex:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback {
+    NSError *error;
+    HKBiologicalSexObject *bioSex = [self.healthStore biologicalSexWithError:&error];
+    NSString *value;
+
+    switch (bioSex.biologicalSex) {
+        case HKBiologicalSexNotSet:
+            value = @"unknown";
+            break;
+        case HKBiologicalSexFemale:
+            value = @"female";
+            break;
+        case HKBiologicalSexMale:
+            value = @"male";
+            break;
+        case HKBiologicalSexOther:
+            value = @"other";
+            break;
+    }
+
+    if(value == nil){
+        NSLog(@"error getting biological sex: %@", error);
+        callback(@[RCTMakeError(@"error getting biological sex", error, nil)]);
+        return;
+    }
+
+    callback(@[[NSNull null], value]);
+}
+
+
+- (void)characteristic_getDateOfBirth:(NSDictionary *)input callback:(RCTResponseSenderBlock)callback {
+    NSError *error;
+    NSDate *dob = [self.healthStore dateOfBirthWithError:&error];
+
+    if(error != nil){
+        NSLog(@"error getting date of birth: %@", error);
+        callback(@[RCTMakeError(@"error getting date of birth", error, nil)]);
+        return;
+    }
+
+    NSString *dobString = [RCTAppleHealthKit buildISO8601StringFromDate:dob];
+
+    callback(@[[NSNull null], dobString]);
+}
+
+
+
+@end