New in SwiftUI 3: Task in SwiftUI 3 and iOS 15

Task modifier was introduced in WWDC21 as part of iOS 15 release. Task modifier can be applied on any SwiftUI view and is another way(better way 😍) to start asynchronous task.

So, if you have been using onAppear to fetch data when your view appears then you can use task instead. Task modifier is more powerful and manages work state automatically so if your view unloads from memory while work is still underway, task takes care of cancelling itself automatically.

Here is what task function signature looks like:

func task(priority: TaskPriority = .userInitiated, _ action: @escaping () async-> Void) -> some View

TaskPriority determines priority for the task while the async task is being created. TaskPriority is set to userInitiated by default so simplest task can be just a trailing closure requesting resource from remote API.

Other values for TaskPriority are:

• high
• medium
• low
• userInitiated (this is default)
• utility
• background

action closure is the closure that SwiftUI will call as async task when your view appears. SwiftUI will automatically cancel this task if the view disappears before async task completes.

Let’s build a simple example by fetching Apple’s current stock data from lil software’s stock api. API itself is very…