Uncaught Error: Got BLE error code 12292 in 1v99 cutting edge but not in release

Ok, just tried this, with the console.log on Serial... If you try:

    console.log("[tap]");
    kb.tap(..., function() {
      console.log("[tap done]");
       ...
    });

both places you call tap then you can see that you can definitely get it into a position where you're calling .tap before the last one has finished, which will cause an error:

[tap]
[tap done]
Starting kbTimer
Clearing kbTimer until finished typing
[tap]
e.state: true
e.time: 1538038837.98822593688
e.lastTime: 1538038837.25543785095
duration: 0.73278808593
[tap done]
Starting kbTimer
Clearing kbTimer until finished typing
[tap]
e.state: false
e.time: 1538038838.10324668884
e.lastTime: 1538038837.98822593688
duration: 0.11502075195
[tap]
[Short press]
Uncaught Error: BLE HID already sending
 at line 1 col 55
NRF.sendHIDReport([0,0,0,0,0,0,0,0],func­tion(){a&&a()})
                                                      ^
in function called from system
[tap done]

However, no BLE error code 12292.

What I'm pretty sure is happening is a few things are all conspiring against you:

• After some inactivity, Espruino will now enter a low-bandwidth, low-power mode. (can be fixed with NRF.setConnectionInterval as that post you linked shows
  
• First thing you do after a button press is print a load of stuff over Bluetooth. This uses up most of the available TX slots (apart from one for HID)
  
• The HID report is sent - all TX slots are used up, but that's fine
  
• Not all of the TX packets get sent the next time (possibly because of negotiation to exit the low power mode)
  
• Espruino gets notified that TX packets were sent - it has no way of knowing which ones, so it assumes HID has been sent and tells your code.
  
• Your code sends another HID packet, but it fails this time because there are no free TX slots
  
  

Basically there's not much I can do about it apart from to only send one TX packet at a time instead of 5, reducing Espruino's TX speed by a factor of 5 - so that is what I've done. Hopefully if you try a cutting edge build now it'll be fixed.

I don't think on the whole people will notice too much as it's really the RX speed that's the killer.