iOS: Write a Foundation object as JSON file to disk

jsonWriting.m

NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:yourObject
                                                   options:(NSJSONWritingOptions) NSJSONWritingPrettyPrinted
                                                     error:&error];
NSString *jsonString;
if (! jsonData) {
  NSLog(@"bv_jsonStringWithPrettyPrint: error: %@", error.localizedDescription);
  jsonString = @"[]";
} else {
  jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
}

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [NSString stringWithFormat:@"%@/%@", documentsDirectory,@"data.json"];

[jsonString writeToFile:filePath atomically:YES encoding:NSUTF8StringEncoding error:&error];
NSLog(@"writing error: %@", error);