[Chapter 15: Grids] AwardsView body indirectly uses `flightNavigation `

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1

Hello @bmorefield ,

Thank you for the great article for Grids. I am wandering about content view refresh for AwardsView when we indirectly use flightNavigation via computed properties:

  @EnvironmentObject var flightNavigation: AppEnvironment

  var awardArray: [AwardInformation] {
    flightNavigation.awardList
  }
    var awardColumns: [GridItem] {
     [GridItem(.adaptive(minimum: 150, maximum: 170))]
   }
    
    var activeAwards: [AwardInformation] {
      awardArray.filter { $0.awarded }
    }
    var inactiveAwards: [AwardInformation] {
      awardArray.filter { !$0.awarded }
    }

How does SwiftUI knows it needs to update AwardsView’s body since it don’t reference flightNavigation directly?

Thanks,
Dzmitry.

2

@Audrey , maybe you could support?
Basically the question “is it safe to do it this way, indirect usage of flightNavigation to make sure body will gets updated every time”

Thanks,
Dzmitry.

3

hi Dzmitry! flightNavigation is an EnvironmentObject, so AwardsView redraws itself whenever it observes a change in flightNavigation. It’s like an ObservedObject, but doesn’t need to be passed as a parameter.

Environment objects are explained in 9.2 Sharing the Environment

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