Showing AVSpeechSynthesizer extension for Speak Selection blog post

AVSpeechSynthesizer+Shared.swift

extension AVSpeechSynthesizer {
    
    static let forSpeakSelection: AVSpeechSynthesizer = {
        let synthesizer = AVSpeechSynthesizer()
        synthesizer.delegate = SpeechDelegate.shared
        return synthesizer
    }()
}

// MARK: - Private

/// Delegate is used to deactivate the audio session when a synthesized utterance has finished.
private class SpeechDelegate: NSObject, AVSpeechSynthesizerDelegate {
    
    static let shared = SpeechDelegate()
    
    func speechSynthesizer(_ synthesizer: AVSpeechSynthesizer, didFinish utterance: AVSpeechUtterance) {
        try? AVAudioSession.sharedInstance().setActive(false)
    }
}