WithAnimation SwiftUI Property Wrapper

WithAnimation.swift

import SwiftUI

@propertyWrapper
struct WithAnimation<T>: DynamicProperty {

    @State private var _internal: T
    private let animation: Animation

    init(wrappedValue: T, _ animation: Animation? = nil) {
        self._internal = wrappedValue
        self.animation = animation ?? .default
    }

    var wrappedValue: T {
        get { _internal }
        nonmutating set {
            withAnimation(animation) {
                _internal = newValue
            }
        }
    }

    var projectedValue: Binding<T> {
        get {
            $_internal.animation(animation)
        }
    }
}

ZWAExample.swift

import SwiftUI

struct WAExample: View {

    @WithAnimation(.spring(duration: 1.5))
    private var isLoading: Bool = false

    var body: some View {
        Button {
            Task {
                isLoading = true
                try? await Task.sleep(for: .milliseconds(2000))
                isLoading = false
            }
        } label: {
            if isLoading {
                ProgressView()
                    .progressViewStyle(.circular)
            } else {
                Text("Fetch")
            }
        }
        .buttonStyle(.borderedProminent)
    }
}