Future Use a Future to handle a single async event

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Create a Future

Many APIs in Dart/Flutter return Futures. To simulate an async event, we can create a future that will resolve after a 5 second delay.

file_type_dartlang futures.dart
var delay = Future.delayed(Duration(seconds: 5));

Handle a Future

A future can either be a success or a error. Use then then to handle a successful resolution and catchError to handle an error.

file_type_dartlang futures.dart
  delay
      .then((value) => print('I have been waiting'))
      .catchError((err) => print(err));

Async Await Syntax

Async-await provides a cleaner (arguably) syntax for writing asynchronous code. The async keyword tells Dart to return a Future, while await pauses the execution of the function until the Future resolves.

file_type_dartlang futures.dart
Future<String> runInTheFuture() async {
  var data = await Future.value('world');

  return 'hello $data';
}

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