more output and error handling

[schnippe]

outputs an error stack instead of ideling. more user feedback about buttons to be pressed for less frustration

[sandeepmistry]

@schnippe thanks for submitting!

Want do you think about using a console.log or console.warn instead of adding error parameter to callback?

My reasoning behind it:

1) It's not a common case 2) Would introduce incompatibility with user's using existing version 3) Makes the API inconsistent, ideally all API calls would have a error parameter, but that's a bigger change.

[schnippe]

I am quite into error handling because it help maintaining a consistent state. I try to manage all cases. The introduction of incompatiblities is aceptable if it helps getting to a stable system.

I could not do any stuctured error handling in a main application if I had no access to the error state of the library.

I like using an error parameter in the callback very much because it is the standard node way of returning an error to a callback. Please see Node 0.12 Doc and search for Callback(

Incrementaly changing this everywhere where needed would help getting to API consistent with node.js and help transitioning to promises and generators.

[sandeepmistry]

It might be better to discuss this and #33 via email or gitter.

Moving forward, I'd like to:

• use noble-device instead of noble directly (my newer BLE node.js module use it)
  • we'll also have to move to adding error parameters on callbacks there as well
• change the discover method to be more like noble's startScanning with an event emitter for discovered SensorTag's

These are "bigger" changes, so working on a branch/fork until complete would be great.

[schnippe]

@sandeepmistry, ok I agree I will use gitter I will try to merge -device and -sensortag if no one else is doing it at the moment. Meanwhile I am trying a distributed Noble approch using multiple raspberries and multiple NOBLE_HCI_DEVICE_IDs.

[sandeepmistry]

With recent changes, this PR is no longer applicable. It would have to be applied to noble-device now ...