What is async Dart?

A Future is defined exactly like a function in Dart, but instead of Void you use Future. If you want to return a value from Future, then you pass it a Type .

then<R> method Null safety Register callbacks to be called when this future completes . When this future completes with a value, the onValue callback will be called with that value. If this future is already completed, the callback will not be called immediately, but will be scheduled in a later microtask.

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.

Async and Await keywords are used to provide a declarative way to define the asynchronous function and use their results . The async keyword is used when we want to declare a function as asynchronous and the await keyword is used only on asynchronous functions.

Async means that this function is asynchronous and you might need to wait a bit to get its result. Await literally means – wait here until this function is finished and you will get its return value. Future is a type that ‘comes from the future’ and returns value from your asynchronous function.