Example

In GraphQL server subscription:

Subscription: {
	myCommand: {
		subscribe: (obj, args, context, info) => {

			const asyncIterator = new EventEmitterAsyncIterator();

			const pushMyCommand = (myCommand) => {
				asyncIterator.pushValue({
					myCommand: myCommand
				});
			};

			asyncIterator.once('return', () => {
				// The client has unsubscribed
			});

			return asyncIterator;
		}
	}
}