How to properly handle incoming TCP/UDP data

Wow, odd that data is missing. It's not usually an issue as Espruino WiFi can receive quite big things (like images) over HTTP without issues.

If you run E.getErrorFlags() does it say anything?

FIFO_FULL would indicate that data has come in faster than Espruino could handle and it had to drop something, so that would be the first port of call.

You could also try adding the turbo mode (wifi.turbo(true,callback) as part of your wifi initialising code) - that'll hugely increase the baud rate from the ESP8266, which might help if the ESP8266 itself had been losing data (it shouldn't though);

Please could you also post up the complete code you're using to read data into the buffer? I'm not sure I'm seeing your tcpOnMessage that does that?

And yeah, it looks to me like the out of memory when dumping is because dumpArray is just turning the array into one big string. If you could make dumpArray call console.log itself with each line of text as it was ready, that would probably help you out a bunch - but if you're not getting the amount of data you expect then it's not worth caring about yet.

I'm not sure I can help much more unless I can reproduce it, so if you don't have any luck with the above, maybe you could:

• Cut your code down to a completely minimal example which you can post up here
  
• Try running that on Node.js on the desktop and see if it works (the code should be pretty much standard JS so it should be fine)
  
• Post up a dump of the complete data you get from Node.js - then I should be able to 'fake' the controller here by making a server which pushes all the data out, and try it with an Espruino WiFi running your code.