What happens if you forget to return a promise or call the async callback in an async generator method?

• A. The generator will crash immediately
• B. Yeoman will wait indefinitely and the lifecycle stalls
• C. Yeoman will proceed with default values
• D. The callback will be automatically invoked

Answer: (B)

Yeoman’s run loop advances only when each asynchronous phase signals completion. In an async generator method, you signal that completion by either returning a promise (for example, using async/await) or by calling the callback you obtain with this.async() and then invoking it when done. If you forget to do either, there’s no signal that the phase is finished, so the run loop waits indefinitely and the lifecycle stalls. To avoid this, make sure any asynchronous work ends with a resolved promise or a invoked callback. For example, an async prompting method can simply return the awaited promise, or you can use this.async() to get a done callback and call it when finished. Without that signal, Yeoman remains stuck in that phase.