onceAsync: reject with custom error on disconnect

[fifthdegree]

This makes it easier to detect when e.g. a command has not received a response due to freeswitch disconnecting.
That's useful because often it's expected that a call may be hung up while a command is running, and it would be nice to be able to differentiate between that and a network error, for example.

[shimaore]

@fifthdegree indeed 🙂 this is called FreeSwitchClosedError in esl-lite.

Side note: not sure what your level of proficiency is with FreeSwitch, but if you're ready to use client-mode you might want to use esl-lite, it might have more to offer than plain esl.

(I haven't announced esl-lite yet because I'm still working on its documentation. esl will stick around for backward compatibility and for its Server mode which can be useful for tests.)

[fifthdegree]

Thanks for the tip, @shimaore. I'll check out esl-lite when I have the chance.
I'm using server mode because I want to send calls from the dialplan to my node.js app (in other words, I only want to control the call in certain cases, like when an option is selected from an ivr). Is there an easy way to do this in client mode?