swift常用命令（精简Swift代码的）

Swift的语法非常好，从这篇译自normi的同名文章就能看出来。

❌ 不推荐的写法 ✅ 推荐的写法

❌ func doSome(result: (Bool) -> ()) {} ✅ typealias BoolBlock = (Bool) -> () /// .... func doSome(result: BoolBlock) {}

func logSome(_ msg: String, detail: String = "default detail") {} logSome("this is msg")

❌ func doSome(info: Info) { if let name = info.name { doOther(name: name) } } ✅ func doSome(info: Info) { guard let name = info.name else { return } doOther(name: name) }

❌ public override func viewDidLoad() { super.viewDidLoad() self.view.backgroundColor = .blue let testView = UIView.init() self.view.addSubview(testView) } ✅ public override func viewDidLoad() { super.viewDidLoad() view.backgroundColor = .blue let testView = UIView() view.addSubview(testView) }

✅ enum Style { case cancel case `default` } class LogProvider { static let `default` = LogProvider() }

✅ func doSome(info: Info) { let name = info.name ?? "default name" }

❌ var text: String? if isMe { text = "Me" } else { text = "other" } ✅ let text = isMe ? "Me" : "other"

❌ view.backgroundColor = UIColor.blue ✅ view.backgroundColor = .blue

❌ class LoginVC: UIViewController, UITextFieldDelegate, UITableViewDataSource, UITableViewDelegate { } ✅ class LoginVC: UIViewController { /// … } extension LoginVC: UITextFieldDelegate { /// … } extension LoginVC: UITableViewDataSource, UITableViewDelegate { /// … }

❌ let name = info.name! ✅ guard let name = info.name else { print("name is nil") return }

❌ var items = Array<String>() var map = Dictionary<String, String>() func doSome() -> Void let callback: () -> Void ✅ var items = [String]() var map = [String : String]() func doSome() let callback: () -> ()

❌ func doSome() -> Int {} let index = doSome() if index == -1 { /// fail } else { /// success } ✅ func doSome() -> Int? {} guard let index = doSome() else { print("fail") return } /// success