robertmryan

func fetchBook(id identifier: String) async throws -> GoogleBook {
    var components = URLComponents(string: "https://www.googleapis.com/books/v1/volumes")
    components?.queryItems = [URLQueryItem(name: "q", value: "{" + identifier + "}")]
    guard let url = components?.url else { throw URLError(.badURL) }

    let (data, _) = try await URLSession.shared.data(from: url)
    return try JSONDecoder().decode(GoogleBook.self, from: data)
}

robertmryan

let recognizer = SFSpeechRecognizer()
weak var task: SFSpeechRecognitionTask?  // note weak reference, as the recognition task keeps strong reference for us while the task is underway

deinit {
    task?.cancel()                       // if still running by the time we deallocate, stop it
}

func startRecognition(of fileURL: URL) {
    task?.cancel()                       // if prior task running, stop it

robertmryan

struct Images {
    static func minus(pointSize: CGFloat? = nil) -> UIImage? {
        image(named: "minus", pointSize: pointSize)
    }

    static func trash(pointSize: CGFloat? = nil) -> UIImage? {
        image(named: "trash", pointSize: pointSize)
    }

    private static func image(named name: String, pointSize: CGFloat? = nil) -> UIImage? {

robertmryan

//  CircleView.h
//
//  Created by Robert Ryan on 4/24/21.

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

IB_DESIGNABLE
@interface CircleView : UIView

robertmryan

func fetchData(symbol: String, completion: @escaping (Result<[StockPrice], Error>) -> Void) { // if you have compilation error here, try `Swift.Result<[StockPrice], Error>` instead
    let url = URL(string: "https://google.com")!

    var request = URLRequest(url: url)
    request.setValue("application/json", forHTTPHeaderField: "Content-Type")
    request.httpMethod = "POST"
    let object = ["symbol": symbol]

    request.httpBody = try! JSONEncoder().encode(object) // or wrap this in `do`-`catch` block and use `try` without the `!`

robertmryan

// The following results in thread explosion:

for idx in 0..<10_000 {
    concurrentQueue.async(group: group) {
        self.something.n += idx
    }
}

// We would instead do

robertmryan

class ModelTest: ObservableObject {
    @Published var strings = [String]()

    func update() {
        DispatchQueue.main.asyncAfter(deadline: .now() + 1) { [weak self] in
            print("now")
            self?.strings = ["test"] // the update, DOES trigger an update of the view
        }
    }
}

robertmryan

class A {
    private var b = B(0)
    private let lock = NSLock()

    deinit {
        NotificationCenter.default.removeObserver(self)
    }

    func changeB(_ i: Int) {
        synchronized { b = B(i) }

robertmryan

//  InvoiceLine.h

@import Foundation;

NS_ASSUME_NONNULL_BEGIN

@interface InvoiceItem : NSObject

@property (nonatomic, copy, nullable) NSString *title;
@property (nonatomic, copy, nullable) NSString *itemDescription; // because `description` has special meaning in `NSObject`, we’ll call this `itemDescription`

robertmryan

public class B {
    private var lock = NSLock()
    private var a: A? = nil

    public func setA() {
        lock.synchronized {
            a = A(0)
        }
    }