Simplify your code with @Entry

If you’ve ever tried to tap into the systems provided by SwiftUI, you are very likely to have come across code like this:

struct MyEnvironmentKey: EnvironmentKey {
    static let defaultValue: Int? = nil
}

extension EnvironmentValues {
    var myEnvironmentValue: Int? {
        get { self[MyEnvironmentKey.self] }
        set { self[MyEnvironmentKey.self] = newValue }
    }
}

This code may seem all right, but if you ever had to add multiple values to the environment, you quickly realised how fast you can fill your codebase with a lot of boilerplate code. Let’s see how to simplify this!

@Entry to the rescue

Starting with iOS 13, we can replace the code above with 3 simple lines.

extension EnvironmentValues {
    @Entry var myEnvironmentValue: Int? = nil
}

After creating an extension for EnvironmentValues you can declare your property as if it was a regular stored property, except it has to be annotated with the @Entry macro. Under the hood this macro generates the necessary code but your codebase is a lot simple.

What else can it do?

The @Entry macro can be used to extend not only the Environment, but also transaction values, container values and focused values