The output wouldn't be readable as it's just a string of binary data - ideally you'd shove it straight into some LEDs so you could see it...
You should be able to output the actual values doing something like this though:
console.log(data.split("").map(function(n) { return n.charCodeAt(0); }).join(" "))
@Gordon started
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 output wouldn't be readable as it's just a string of binary data - ideally you'd shove it straight into some LEDs so you could see it...
You should be able to output the actual values doing something like this though: