What is async and await in Flutter?

When an async function is called, a Future is immediately returned and the body of the function is executed later . As the body of the async function is executed, the Future returned by the function call will be completed along with its result. In the above example, calling demo() results in the Future.

The difference between both is that async* will always return a Stream and offer some syntax sugar to emit a value through the yield keyword . async gives you a Future and async* gives you a Stream. When users marks a function as async or async* allows it to use async/await keyword to use a Future.

await can be used on its own with JavaScript modules. Note: The purpose of async / await is to simplify the syntax necessary to consume promise-based APIs . The behavior of async / await is similar to combining generators and promises. Async functions always return a promise.

await is meant to interrupt the process flow until the async method has finished . then however does not interrupt the process flow (meaning the next instructions will be executed) but enables you to run code when the async method is finished.4 Şub 2019

When you await an asynchronous function, the execution of the code within the caller suspends while the async operation is executed. When the operation is completed, the value of what was awaited is contained within a Future object. Take a look at the simple program below.