How do I use property wrappers effectively?

Property wrappers in Swift provide a convenient way to encapsulate and manage the storage and behavior of properties. They allow developers to define custom logic around property access, enabling features like validation, lazy loading, and more without cluttering the property’s code. Here’s how to use property wrappers effectively in your Swift code:

Creating a Property Wrapper

A property wrapper is defined using a struct or class that implements a wrappedValue property. This property manages the actual underlying value.

Using a Property Wrapper

Once you define a property wrapper, you can easily apply it to properties in your classes or structs.

Example:


        @propertyWrapper
        struct Validated {
            @available private var value : String
            
            var wrappedValue: String {
                get { value }
                set {
                    if isValid(newValue) {
                        value = newValue
                    } else {
                        fatalError("Invalid value!")
                    }
                }
            }

            init(wrappedValue: String) {
                self.value = wrappedValue
            }

            private func isValid(_ value: String) -> Bool {
                return value.count > 3
            }
        }

        struct User {
            @Validated var username: String
        }
        
        let user = User(username: "john") // This will trigger fatal error

How do I use property wrappers effectively?

Creating a Property Wrapper

Using a Property Wrapper

Example:

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How do I use property wrappers effectively?

Creating a Property Wrapper

Using a Property Wrapper

Example:

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Popular Topics

Recent Languages