Handy debugging extension on SwiftUI's Animation

Animation+Slow.swift

import SwiftUI

/// On macOS, modifying an Animation with .currentSpeed(), or using the .current static property
/// allows for easy animation debugging by holding down the Shift key when triggering the animation.
/// When the animation is triggered while the Shift key is pressed, it will be played in slow motion.
/// Using this extension has no effect when targeting other OSes or when building for release.
extension Animation {

    static var currentSpeed: Double {
        #if DEBUG
        #if os(macOS)
        if NSEvent.modifierFlags.contains(.shift) {
            return 0.1
        } else {
            return 1
        }
        #else
        return 1
        #endif
        #else
        return 1
        #endif
    }

    static var current: Animation { Animation.default.currentSpeed() }

    func currentSpeed() -> Animation {
        speed(Self.currentSpeed)
    }

}