The issue is that the library esp provides takes a buffer - and the espruino calls send one byte at a time - so it's taking a buffer, and sending it a single byte - so it's really inefficient.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
The issue is that the library esp provides takes a buffer - and the espruino calls send one byte at a time - so it's taking a buffer, and sending it a single byte - so it's really inefficient.