extension DispatchQueue { static func background(delay: Double = 0.0, background: (()->Void)? = nil, completion: (() -> Void)? = nil) { DispatchQueue.global(qos: .background).async { background?() if let completion = completion { DispatchQueue.main.asyncAfter(deadline: .now() + delay, execute: { completion() }) } } }
}
// USAGE
DispatchQueue.background(delay: 3.0, background: { // do something in background
}, completion: { // when background job finishes, wait 3 seconds and do something in main thread
})
DispatchQueue.background(background: { // do something in background
}, completion:{ // when background job finished, do something in main thread
})
DispatchQueue.background(delay: 3.0, completion:{ // do something in main thread after 3 seconds
})