ZeroUI.md

ZeroUI

Zero in SwiftUI, UIKit, and AppKit.

Overview

Put the client in the environment, and read queries with @ZeroQuery. A view updates when its query's rows change:

@main
struct IssuesApp: App {
  @State private var zero = try! Zero(
    schema: .app, context: auth, mutators: [IssueMutators.create], options: options)

  var body: some Scene {
    WindowGroup { IssueList().zero(zero) }
  }
}

struct IssueList: View {
  @ZeroQuery(IssueQueries.open()) var issues

  var body: some View {
    List(issues) { Text($0.title) }
      .overlay { if $issues.resultType == .unknown { ProgressView() } }
  }
}

Make the client once, in the App as here, or in an object the app owns. Don't make it in a view's @State initializer. SwiftUI runs that initializer each time it re-creates the view, and each client it makes connects before being dropped.

The zero-react hooks map to it as follows:

zero-react	ZeroUI
<ZeroProvider zero={zero}>	.zero(zero)
useZero()	@Environment(\.zero)
useQuery(query)	@ZeroQuery(query) var rows
useConnectionState()	zero.connection.state

In UIKit and AppKit, DiffableAdapter feeds a diffable data source from a MaterializedView. Each row is an item, identified by its primary key, and its cell is reconfigured when the row changes. LiveQuery in Zero is the observable to use elsewhere.

ZeroUI re-exports Zero.

Topics

SwiftUI

• ZeroQuery
• QueryState

UIKit and AppKit

• DiffableAdapter