Merge pull request #24 from locly/master

Drop empty range calls

Author: frostney

README.md

@@ -147,6 +147,12 @@ Beacons.stopUpdatingLocation();
 
 This method should be called when you don't need to receive location-based information and want to save battery power.
 
+### Beacons.shouldDropEmptyRanges
+```javascript
+Beacons.shouldDropEmptyRanges(true);
+```
+Call this method to stop sending the `beaconsDidRange` event when the beacon list is empty. This can be useful when listening to multiple beacon regions and can reduce cpu usage by 1-1.5%.
+
 ## Events
 To listen to events we need to call `DeviceEventEmitter.addListener` (`var {DeviceEventEmitter} = require('react-native')`) where the first parameter is the event we want to listen to and the second is a callback function that will be called once the event is triggered.
 

RNBeacon.m

@@ -17,6 +17,7 @@
 @interface RNBeacon() <CLLocationManagerDelegate>
 
 @property (strong, nonatomic) CLLocationManager *locationManager;
+@property (assign, nonatomic) BOOL dropEmptyRanges;
 
 @end
 
@@ -35,6 +36,7 @@ - (instancetype)init
 
         self.locationManager.delegate = self;
         self.locationManager.pausesLocationUpdatesAutomatically = NO;
+        self.dropEmptyRanges = NO;
     }
 
     return self;
@@ -153,6 +155,11 @@ - (NSString *)stringForProximity:(CLProximity)proximity {
     [self.locationManager stopUpdatingLocation];
 }
 
+RCT_EXPORT_METHOD(shouldDropEmptyRanges:(BOOL)drop)
+{
+    self.dropEmptyRanges = drop;
+}
+
 -(NSString *)nameForAuthorizationStatus:(CLAuthorizationStatus)authorizationStatus
 {
     switch (authorizationStatus) {
@@ -195,6 +202,9 @@ - (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *
 -(void) locationManager:(CLLocationManager *)manager didRangeBeacons:
 (NSArray *)beacons inRegion:(CLBeaconRegion *)region
 {
+    if (self.dropEmptyRanges && beacons.count == 0) {
+        return;
+    }
     NSMutableArray *beaconArray = [[NSMutableArray alloc] init];
 
     for (CLBeacon *beacon in beacons) {