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Merge pull request #38 from connor-ricks/task/shared-state
✨ Adds SharedState.
2 parents 58592bd + d74cef4 commit 40053cd

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‎.swiftpm/xcode/package.xcworkspace/contents.xcworkspacedata‎

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‎.swiftpm/xcode/xcshareddata/xcschemes/SharedState.xcscheme‎

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<?xml version="1.0" encoding="UTF-8"?>
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<Scheme
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LastUpgradeVersion = "1520"
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version = "1.7">
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<BuildAction
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parallelizeBuildables = "YES"
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buildImplicitDependencies = "YES">
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<BuildActionEntries>
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<BuildActionEntry
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buildForTesting = "YES"
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buildForRunning = "YES"
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buildForProfiling = "YES"
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buildForArchiving = "YES"
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buildForAnalyzing = "YES">
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<BuildableReference
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BuildableIdentifier = "primary"
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BlueprintIdentifier = "SharedState"
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BuildableName = "SharedState"
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BlueprintName = "SharedState"
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ReferencedContainer = "container:">
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</BuildableReference>
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</BuildActionEntry>
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</BuildActionEntries>
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</BuildAction>
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<TestAction
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buildConfiguration = "Debug"
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selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
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selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
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shouldUseLaunchSchemeArgsEnv = "YES">
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<TestPlans>
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<TestPlanReference
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reference = "container:Tests/SharedStateTests/SharedState.xctestplan"
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default = "YES">
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</TestPlanReference>
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</TestPlans>
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</TestAction>
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<LaunchAction
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buildConfiguration = "Debug"
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selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
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selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
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launchStyle = "0"
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useCustomWorkingDirectory = "NO"
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ignoresPersistentStateOnLaunch = "NO"
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debugDocumentVersioning = "YES"
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debugServiceExtension = "internal"
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allowLocationSimulation = "YES">
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</LaunchAction>
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<ProfileAction
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buildConfiguration = "Release"
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shouldUseLaunchSchemeArgsEnv = "YES"
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savedToolIdentifier = ""
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useCustomWorkingDirectory = "NO"
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debugDocumentVersioning = "YES">
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<MacroExpansion>
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<BuildableReference
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BuildableIdentifier = "primary"
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BlueprintIdentifier = "SharedState"
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BuildableName = "SharedState"
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BlueprintName = "SharedState"
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ReferencedContainer = "container:">
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</BuildableReference>
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</MacroExpansion>
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</ProfileAction>
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<AnalyzeAction
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buildConfiguration = "Debug">
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</AnalyzeAction>
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<ArchiveAction
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buildConfiguration = "Release"
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revealArchiveInOrganizer = "YES">
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</ArchiveAction>
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</Scheme>

‎.swiftpm/xcode/xcshareddata/xcschemes/swift-nibbles-Package.xcscheme‎

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ReferencedContainer = "container:">
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</BuildableReference>
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</BuildActionEntry>
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<BuildActionEntry
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buildForTesting = "YES"
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buildForRunning = "YES"
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buildForProfiling = "YES"
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buildForArchiving = "YES"
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buildForAnalyzing = "YES">
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<BuildableReference
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BuildableIdentifier = "primary"
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BlueprintIdentifier = "SharedState"
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BuildableName = "SharedState"
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BlueprintName = "SharedState"
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ReferencedContainer = "container:">
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</BuildableReference>
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</BuildActionEntry>
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</BuildActionEntries>
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</BuildAction>
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<TestAction
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ReferencedContainer = "container:">
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</BuildableReference>
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</TestableReference>
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<TestableReference
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skipped = "NO">
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<BuildableReference
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BuildableIdentifier = "primary"
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BlueprintIdentifier = "SharedStateTests"
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BuildableName = "SharedStateTests"
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BlueprintName = "SharedStateTests"
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ReferencedContainer = "container:">
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</BuildableReference>
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</TestableReference>
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</Testables>
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</TestAction>
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<LaunchAction

‎Package.resolved‎

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‎Package.swift‎

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@@ -15,9 +15,13 @@ let package = Package(
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.library(name: "Extensions", targets: ["Extensions"]),
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.library(name: "Fuse", targets: ["Fuse"]),
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.library(name: "Identified", targets: ["Identified"]),
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.library(name: "SharedState", targets: ["SharedState"]),
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.library(name: "Stash", targets: ["Stash"]),
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.plugin(name: "Create TCA Feature", targets: ["Create TCA Feature"])
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],
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dependencies: [
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.package(url: "https://github.com/pointfreeco/swift-concurrency-extras", from: "1.1.0"),
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],
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targets: [
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.target(name: "Exchange"),
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.testTarget(name: "ExchangeTests", dependencies: ["Exchange"]),
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.target(name: "Identified"),
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.testTarget(name: "IdentifiedTests", dependencies: ["Identified"]),
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.target(name: "SharedState", dependencies: ["Fuse", .product(name: "ConcurrencyExtras", package: "swift-concurrency-extras"),]),
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.testTarget(name: "SharedStateTests", dependencies: ["SharedState"]),
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.target(name: "Stash"),
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.testTarget(name: "StashTests", dependencies: ["Stash"]),
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‎Sources/SharedState/SharedState.swift‎

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//
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// MIT License
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//
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// Copyright (c) 2024 Connor Ricks
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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// SOFTWARE.
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import Combine
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import ConcurrencyExtras
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import Foundation
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import Fuse
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public typealias SharedStateUpdateBlock<T> = (_ old: T, _ new: T) async -> Void
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/// A box that encapsulates an object allowing others to subscribe to and monitor changes to the state.
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///
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/// Useful when you have multiple services or features that wish to subscribe to changes.
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///
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/// Frequently use in PointFree's TCA architecture to subsribe long-running effects to shared state changes.
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///
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/// ```
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/// let settings = SharedState(Settings(theme: .dark), onChange: { old, new in
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/// datastore.saveTheme(new)
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/// })
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///
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/// for await theme in settings {
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/// update(for settings)
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/// }
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///
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/// for await theme in settings[stream: \.theme] {
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/// update(for theme)
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/// }
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/// ```
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@dynamicMemberLookup
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public struct SharedState<T: Equatable & Sendable>: @unchecked Sendable {
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// MARK: Properties
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private let state: LockIsolated<T>
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private let subject = PassthroughSubject<T, Never>()
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private let onChange: SharedStateUpdateBlock<T>?
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// MARK: Initializers
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public init(_ value: T, onChange: SharedStateUpdateBlock<T>? = nil) {
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self.state = LockIsolated(value)
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self.onChange = onChange
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}
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// MARK: Stream
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public subscript<Value>(dynamicMember keyPath: KeyPath<T, Value>) -> Value {
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self()[keyPath: keyPath]
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}
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public subscript<Value: Equatable>(
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stream keyPath: KeyPath<T, Value>,
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bufferingPolicy: AsyncStream<Value>.Continuation.BufferingPolicy = .unbounded
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) -> AsyncStream<Value> {
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return subject
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.map(keyPath)
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.filter { state.value[keyPath: keyPath] != $0 }
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.values(bufferingPolicy: bufferingPolicy)
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.eraseToStream()
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}
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// MARK: Publisher
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public subscript<Value: Equatable>(
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publisher keyPath: KeyPath<T, Value>
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) -> AnyPublisher<Value, Never> {
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return subject
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.map(keyPath)
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.filter { state.value[keyPath: keyPath] != $0 }
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.eraseToAnyPublisher()
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}
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public var publisher: AnyPublisher<T, Never> {
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subject.eraseToAnyPublisher()
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}
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// MARK: Methods
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public func callAsFunction() -> T {
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state.value
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}
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private func set(_ newValue: T) async {
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let oldValue = state.value
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state.withValue {
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$0 = newValue
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subject.send(newValue)
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}
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await onChange?(oldValue, newValue)
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}
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public func stream(bufferingPolicy: AsyncStream<T>.Continuation.BufferingPolicy = .unbounded) -> AsyncStream<T> {
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subject
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.filter { state.value != $0 }
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.values(bufferingPolicy: bufferingPolicy).eraseToStream()
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}
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public func mutate(_ operation: (inout T) async throws -> Void) async rethrows {
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var value = self()
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try await operation(&value)
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await set(value)
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// Yielding in order to allow subscribers time to react before proceeding onwards.
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await Task.yield()
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}
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}

‎Tests/SharedStateTests/SharedState.xctestplan‎

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{
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"configurations" : [
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{
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"id" : "3AD1685E-93AE-4C99-B1DD-6BFF0C4A1EC1",
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"name" : "Configuration 1",
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"options" : {
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}
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}
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],
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"defaultOptions" : {
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},
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"testTargets" : [
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{
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"parallelizable" : true,
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"target" : {
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"containerPath" : "container:",
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"identifier" : "SharedStateTests",
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"name" : "SharedStateTests"
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}
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}
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],
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"version" : 1
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}

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