iOS 12.0 Alternative to Using Deprecated archiveRootObject:toFile:

Question

With iOS 12, archiveRootObject:toFile:has been deprecated. Can anyone suggest a streamlined alternative to archiving objects to a file?

//Generic example of archiver prior to iOS 12.0    
-(BOOL) archive:(id)archiveObject withFileName:(NSString*)filename
{
    NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
    return [NSKeyedArchiver archiveRootObject:archiveObject toFile:path];
}

Answer 1

Thanks to @vadian for the hint, here's what I've come up with to do archiving and unarchiving under iOS 12:

NSError *error = nil;

NSString *docsDir;
NSArray *dirPaths;

//Get the device's data directory:
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = [dirPaths objectAtIndex:0];
NSString *databasePath = [[NSString alloc] initWithString: [docsDir stringByAppendingPathComponent:@"appData.data"]];

//Archive using iOS 12 compliant coding:
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:@"foo" requiringSecureCoding:NO error:&error];
[data writeToFile:databasePath options:NSDataWritingAtomic error:&error];
NSLog(@"Write returned error: %@", [error localizedDescription]);

//Unarchive the data:
NSData *newData = [NSData dataWithContentsOfFile:databasePath];
NSString *fooString = [NSKeyedUnarchiver unarchivedObjectOfClass:[NSString class] fromData:newData error:&error];