如何在 swift 中使用异步/等待同时运行多个 API 调用？

Question

As per the new Structured Concurrency in Swift, we can await a API call which is done in an async context, But I want to make multiple API calls simultaneously, for example,

profileData = await viewModel.getProfileData()
userCardData = await viewModel.getCardDetails()

The problem in the above case is CardDetails is fetched only after fetching the profile data.

Answer 1

It can be achieved using the async let . This special syntax allows you to group several asynchronous calls and await them together, Example,

async let profileData = viewModel.getProfileData()
async let userCardData = viewModel.getCardDetails()

The above statement indicated that profileData and userCardData , will be available at some point of time in future, just like a promise.

Now in order to use profileData and userCardData we need to use await, incase the data is fetched and available it would return immediately, or it suspend until the data is available.

The value from the above request can be used like,

let (fetchedProfileData, fetchedUserCardData) = try await (profileData, userCardData)