CODEWITHSUNDEEP
iosswiftmvvmswiftui
Damian Dudycz
Damian Dudycz

Reputation: 2800

How does SwiftUI know what environmentObject to assign to which variable

Lets say I have a View with Environment Object like this:

struct MyView: View {
    @EnvironmentObject
    var viewModel: RegisterViewModel
}

and somewhere in ancestor I would provide this object like this:

NavigationView {
    LoginView()
}
.environmentObject(RegisterViewModel())

What is the mechanics of actually assigning this value to var viewModel. Nowhere in my code I needed to specify the name of variable, and yet it's correctly assigned. What will happened if I have few environment objects of the same type?

Upvotes: 1

Views: 686

Answers (1)

pawello2222
pawello2222

Reputation: 54516

EnvironmentObjects are identified by type.

SwiftUI just looks for environment variables for a specific type (here it's RegisterViewModel) and uses the first one it finds.

This code puts RegisterViewModel to the environment:

.environmentObject(RegisterViewModel())

Then, when building a View, SwiftUI looks for a RegisterViewModel type in the environment:

@EnvironmentObject var viewModel: RegisterViewModel

More details:

Upvotes: 2

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