Adds a polling task to a SwiftUI view that repeatedly performs an asynchronous action at a specified interval.

SwiftUITask+Polling.swift

import SwiftUI

public extension View {
    /// Adds a polling task to a SwiftUI view that repeatedly performs an asynchronous action at a specified interval.
    ///
    /// This method wraps SwiftUI's `.task(id:priority:)` modifier to repeatedly invoke a given asynchronous `action`
    /// until the task is cancelled. It is useful for scenarios like periodic data refreshing.
    ///
    /// - Parameters:
    ///   - value: A value to identify the task. Changing this value will cancel and restart the task. Must conform to `Equatable`.
    ///   - interval: The time interval (in seconds) between repeated executions of the action. Evaluated as an autoclosure on each iteration.
    ///   - runImmediately: A Boolean value that determines whether to run the `action` immediately upon task start (`true`),
    ///     or wait until the first interval has passed (`false`). Defaults to `true`.
    ///   - priority: The task's priority. Defaults to `.userInitiated`.
    ///   - action: An asynchronous closure to be executed on each polling cycle. The closure must be `@Sendable`.
    ///
    /// - Returns: A view with an attached polling task.
    ///
    /// ### Example
    /// ```swift
    /// .pollingTask(
    ///     id: model.refreshID,
    ///     interval: 30,
    ///     runImmediately: true
    /// ) {
    ///     await model.fetchData()
    /// }
    /// ```
    func pollingTask<T>(
        id value: T,
        interval: @autoclosure @escaping () -> TimeInterval,
        runImmediately: Bool = true,
        priority: TaskPriority = .userInitiated,
        _ action: @escaping @Sendable () async -> Void
    ) -> some View where T: Equatable {
        self.task(id: value, priority: priority) {
            repeat {
                if runImmediately { await action() }
                try? await Task.sleep(for: .seconds(interval()))
                if !runImmediately { await action() }
            } while (!Task.isCancelled)
        }
    }
    
    /// Adds a polling task to a SwiftUI view that repeatedly performs an asynchronous action at a specified interval.
    func pollingTask(
        interval: @autoclosure @escaping () -> TimeInterval,
        runImmediately: Bool = true,
        priority: TaskPriority = .userInitiated,
        _ action: @escaping @Sendable () async -> Void
    ) -> some View {
        self.task(priority: priority) {
            repeat {
                if runImmediately { await action() }
                try? await Task.sleep(for: .seconds(interval()))
                if !runImmediately { await action() }
            } while (!Task.isCancelled)
        }
    }
}