A library for helping build high quality forms in SwiftUI and TCA
Add SwiftUI-style form submit delegate
Woodrow Melling
(May 22, 2026, 12:40 PM -0600)
d05d08ea
ef593ebb
+162
-9
+46
-9
Sources/ComposableForms/Form.swift
+46
-9
Sources/ComposableForms/Form.swift
···
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@Feature
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public struct Form<Value> {
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public init(fields: [FormFieldDefinition<Value>]) {
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self.fields = fields
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self.init(fields: fields, submitDelegate: { _ in })
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}
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public init(
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@FormFieldDefinitionBuilder<Value> fields: () -> [FormFieldDefinition<Value>]
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) {
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self.fields = fields()
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self.init(fields: fields())
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}
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private init(
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fields: [FormFieldDefinition<Value>],
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submitDelegate: @escaping (Value) throws -> Void
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) {
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self.fields = fields
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self.submitDelegate = submitDelegate
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}
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public static func Field<Root, FieldValue: Equatable>(
···
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case submittedForm
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}
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public func onSubmit(_ action: @escaping (Value) throws -> Void) -> Self {
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Self(fields: self.fields, submitDelegate: action)
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}
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private let fields: [FormFieldDefinition<Value>]
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private let submitDelegate: (Value) throws -> Void
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public var body: some Feature {
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let submit: (Value) -> Void = { value in
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store.addTask {
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try self.submitDelegate(value)
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}
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}
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let runAsyncValidation: (PendingAsyncValidation<Value>) -> Void = { validation in
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store.addTask {
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let errors = await validation.validateAsync(validation.value, validation.trigger)
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var submitValue: Value?
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try store.modify { state in
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guard validation.observedValue(state.value) == validation.validatedValue else {
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return
···
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} else {
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state.validation[validation.field] = FieldValidationState(errors: errors)
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}
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state.finishSubmissionIfValidationSettled()
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if state.finishSubmissionIfValidationSettled() {
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submitValue = state.value
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}
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}
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if let submitValue {
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try self.submitDelegate(submitValue)
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}
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}
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}
···
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runAsyncValidation: runAsyncValidation
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)
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}
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state.updateSubmissionStatusAfterSubmit()
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if state.updateSubmissionStatusAfterSubmit() {
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submit(state.value)
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}
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}
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}
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.onChange(of: store.focusedField) { oldField, newField, state in
···
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}
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extension Form.State {
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fileprivate mutating func finishSubmissionIfValidationSettled() {
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fileprivate mutating func finishSubmissionIfValidationSettled() -> Bool {
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guard self.submissionStatus == .submitting, !self.isValidating else {
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return
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return false
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}
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guard !self.hasErrors else {
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self.submissionStatus = .idle
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return false
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}
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self.submissionStatus = self.hasErrors ? .idle : .submitted
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self.submissionStatus = .submitted
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return true
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}
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fileprivate func hasErrors(for field: AnyHashable) -> Bool {
···
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self.validation[field] != nil
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}
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-
fileprivate mutating func updateSubmissionStatusAfterSubmit() {
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fileprivate mutating func updateSubmissionStatusAfterSubmit() -> Bool {
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if self.isValidating {
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self.submissionStatus = .submitting
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return false
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} else {
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self.submissionStatus = self.hasErrors ? .idle : .submitted
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guard !self.hasErrors else {
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self.submissionStatus = .idle
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return false
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}
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self.submissionStatus = .submitted
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return true
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}
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}
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}
+116
Tests/ComposableFormsTests/FormTests.swift
+116
Tests/ComposableFormsTests/FormTests.swift
···
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import ComposableArchitecture2
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+
import Foundation
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import Testing
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@testable import ComposableForms
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···
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@Test
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@MainActor
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func submittedFormCallsOnSubmitWhenValid() async {
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let value = TestValue(name: "Blob", status: "draft")
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let submitProbe = SubmitProbe<TestValue>()
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let store = TestStore(initialState: TestForm.State(value: value)) {
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TestForm()
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.onSubmit { submitProbe.submit($0) }
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}
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+
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let task = store.send(.submittedForm) {
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$0.submissionStatus = .submitted
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$0.validation[FieldID.name] = .valid
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$0.validation[FieldID.status] = .valid
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}
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await task?.value
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+
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#expect(submitProbe.values() == [value])
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}
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+
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@Test
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@MainActor
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func submittedFormDoesNotCallOnSubmitWhenInvalid() {
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let submitProbe = SubmitProbe<TestValue>()
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let store = TestStore(initialState: TestForm.State(value: TestValue())) {
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TestForm()
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.onSubmit { submitProbe.submit($0) }
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}
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+
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store.send(.submittedForm) {
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$0.validation[FieldID.name] = .invalid(.nameRequired)
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$0.validation[FieldID.status] = .invalid(.statusRequired)
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}
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+
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#expect(submitProbe.values().isEmpty)
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}
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+
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@Test
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@MainActor
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func valueChangeClearsSubmittedStatus() {
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let store = TestStore(
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initialState: TestForm.State(
···
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@Test
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@MainActor
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+
func submittedFormCallsOnSubmitAfterAsyncValidationSucceeds() async {
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let submitProbe = SubmitProbe<AsyncTestValue>()
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let validationProbe = AsyncValidationProbe()
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let value = AsyncTestValue(username: "blob")
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let store = TestStore(initialState: AsyncTestForm.State(value: value)) {
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AsyncTestForm(probe: validationProbe)
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.onSubmit { submitProbe.submit($0) }
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}
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+
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let task = store.send(.submittedForm) {
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$0.submissionStatus = .submitting
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$0.validation[AsyncFieldID.username] = .validating()
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}
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#expect(submitProbe.values().isEmpty)
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+
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await validationProbe.waitForValidation()
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await validationProbe.finish(.valid)
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await task?.value
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let expectation = store.expect {
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$0.submissionStatus = .submitted
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$0.validation[AsyncFieldID.username] = .valid
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}
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await expectation?.value
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+
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#expect(submitProbe.values() == [value])
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}
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+
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@Test
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+
@MainActor
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func asyncValidationIgnoresStaleResults() async {
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let probe = AsyncValidationProbe()
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let store = TestStore(
···
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await probe.finish(.invalid(.usernameUnavailable))
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await task?.value
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#expect(store.state.validation[AsyncFieldID.username] == nil)
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}
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+
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@Test
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@MainActor
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func staleAsyncValidationDoesNotCallOnSubmit() async {
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let submitProbe = SubmitProbe<AsyncTestValue>()
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let validationProbe = AsyncValidationProbe()
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let store = TestStore(
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initialState: AsyncTestForm.State(
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value: AsyncTestValue(username: "blob")
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)
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) {
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AsyncTestForm(probe: validationProbe)
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.onSubmit { submitProbe.submit($0) }
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}
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+
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let task = store.send(.submittedForm) {
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$0.submissionStatus = .submitting
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$0.validation[AsyncFieldID.username] = .validating()
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}
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await validationProbe.waitForValidation()
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+
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store.modify {
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$0.value.username = "fresh"
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} changes: {
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$0.submissionStatus = .idle
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$0.validation.removeValue(forKey: AsyncFieldID.username)
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}
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+
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await validationProbe.finish(.valid)
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await task?.value
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#expect(submitProbe.values().isEmpty)
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}
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@Test
···
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private typealias NestedTestForm = Form<NestedValue>
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private typealias AsyncTestForm = Form<AsyncTestValue>
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private typealias SubmitOnlyTestForm = Form<AsyncTestValue>
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+
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+
private final class SubmitProbe<Value>: @unchecked Sendable {
549
+
private let lock = NSLock()
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+
private var submittedValues: [Value] = []
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+
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+
func submit(_ value: Value) {
553
+
self.lock.lock()
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+
defer { self.lock.unlock() }
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+
self.submittedValues.append(value)
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+
}
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+
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+
func values() -> [Value] {
559
+
self.lock.lock()
560
+
defer { self.lock.unlock() }
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+
return self.submittedValues
562
+
}
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+
}
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private actor AsyncValidationProbe {
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private var continuations: [CheckedContinuation<ValidationResult, Never>] = []