Conditional ViewModifier issue

[vladyslavsosiuk]

Hello. Thank you for a great code sample.

I found that it uses a conditional view modifier which is an incorrect implementation in SwiftUI and causes hard-to-track bugs. The antipattern described in more details here: https://www.objc.io/blog/2021/08/24/conditional-view-modifiers/

Unfortunately, I don't have a possibility to open a PR with a fix, but I can provide suggestions. Instead of returning modified view if the active argument is true we should pass that argument down to the ShimmerView and compute the duration of the animation based on that argument:

AnimatedMask(
    isActive: isActive,
    phase: phase
).animation(
    .linear(duration: isActive ? duration : 0) // FW: This is a correct way to stop animation. If using `isActive ? .linear(...) : .none` instead then the animation would be choppy. https://stackoverflow.com/questions/61830571/whats-causing-swiftui-nested-view-items-jumpy-animation-after-the-initial-drawi/61841018#61841018
    .repeatForever(autoreverses: bounce)
)

We will also need to retrigger the animation if view didn't reappear but the isActive property flipped from false to true

.onChange(of: isActive) { isActive in
    if isActive {
        phase = 0.8
    } else {
        phase = 0
    }
}

We should pass down the isActive argument down to the AnimatedMask modifier and down to the GradientMaskModifier so that we can compute edgeColor opacity and return 1 if isActive is false. Let me know if you need more details.