# Custom Property Wrapper that Updates View

**URL:** <https://forums.swift.org/t/custom-property-wrapper-that-updates-view/31782>\
**Category:** Using Swift\
**Tags:** off-topic, swiftui, propertywrapper\
**Created:** [December 17, 2019, 10:41pm UTC](https://forums.swift.org/t/custom-property-wrapper-that-updates-view/31782 "2019-12-17T22:41:47Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![Morten\_Bek\_Ditlevsen](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/morten_bek_ditlevsen/32/28133_2.png) [@Morten\_Bek\_Ditlevsen](https://forums.swift.org/u/Morten_Bek_Ditlevsen)\
**Post date:** [December 18, 2019, 6:42pm UTC](https://forums.swift.org/t/custom-property-wrapper-that-updates-view/31782/2 "2019-12-18T18:42:39Z")

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To the best of my understanding the re-evaluation and re-rendering of a SwiftUI View can only be triggered by the built-in property wrappers like @State and @ObservedObject.

Though property wrapper composition is not supported in Swift 5.1.3, it -is- on the master branch development snapshot tool chains on [Swift.org](http://Swift.org).  
This means that your custom property wrapper type can conform to ObservableObject and then you can indeed compose @ObservedObject with your own wrapper.

I have an example of something quite similar to yours running - also with Firebase as the data source.

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