Realm helper

RealmExtension.swift

import Foundation
import RealmSwift

var realmConfiguration: Realm.Configuration?

public typealias VoidCompletion = () -> Void

extension Realm {
    
    static var shared: Realm? {
        if let configuration = realmConfiguration {
            return try? Realm(configuration: configuration)
        } else {
            let configuration = Realm.Configuration(
                deleteRealmIfMigrationNeeded: true
            )
            
            return try? Realm(configuration: configuration)
        }
    }
    
    static func execute(_ execution: @escaping (Realm) -> Void, completion: VoidCompletion? = nil) {
        var backgroundTaskId: UIBackgroundTaskIdentifier?
        
        backgroundTaskId = UIApplication.shared.beginBackgroundTask(withName: "reeichert.dev.realm.background", expirationHandler: {
            backgroundTaskId = UIBackgroundTaskInvalid
        })
        
        if let backgroundTaskId = backgroundTaskId {
            DispatchQueue.global(qos: .background).async {
                guard let realm = self.shared else { return }
                
                try? realm.write {
                    execution(realm)
                }
                
                DispatchQueue.main.async {
                    completion?()
                }
                
                UIApplication.shared.endBackgroundTask(backgroundTaskId)
            }
        }
    }
    
    static func executeOnMainThread(_ execution: @escaping (Realm) -> Void) {
        guard let realm = self.shared else { return }
        
        try? realm.write {
            execution(realm)
        }
    }
    
    // MARK: Mutate
    // This method will add or update a Realm's object.
    static func delete(_ object: Object) {
        guard !object.isInvalidated else { return }
        
        self.execute({ realm in
            realm.delete(object)
        })
    }
    
    // This method will add or update a Realm's object.
    static func update(_ object: Object) {
        self.execute({ realm in
            realm.add(object, update: true)
        })
    }
    
    // This method will add or update a list of some Realm's object.
    static func update<S: Sequence>(_ objects: S) where S.Iterator.Element: Object {
        self.execute({ realm in
            realm.add(objects, update: true)
        })
    }
    
}