Swift 中可选的闭包属性

Swift 中的可选闭包属性是一种非常有用的特性，它可以让我们更加灵活地处理闭包。在本文中，我们将探讨可选闭包属性的作用和用法，并通过案例代码来说明。

swift
var optionalClosure: (() -> Void)?

swift
var optionalClosure: (() -> Void)?
func doSomething() {
    print("Do something.")
}
optionalClosure = doSomething
if let closure = optionalClosure {
    closure()
}

swift
func makeRequest(completion: (() -> String)?) {
    // 模拟网络请求
    DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
        if let result = completion {
            let response = result()
            print("Response: \(response)")
        } else {
            print("Request completed.")
        }
    }
}
var optionalClosure: (() -> String)?
optionalClosure = {
    return "Request finished successfully."
}
makeRequest(completion: optionalClosure)