switch-johnny-five.js

console.log('Hello Pi')

var raspi = require('raspi-io')
var five = require('johnny-five')
var board = new five.Board({
  io: new raspi()
})

board.on('ready', function() {
  console.log('Board ready')

  var output = new five.Pin({
    pin: 0,
    mode: 1,
    freq: 1
  })

  var input = new five.Pin({
    pin: 2,
    mode: 0,
    freq: 1
  })

  input.read(function(error, value) {
    output.write(value)
  })
})

Note that some of this extra latency compared to using the firmata protocol directly can be traced to a 5ms debounce in switch
https://github.com/rwaldron/johnny-five/blob/master/lib/switch.js#L35-L46

Update revision two so directly reading / writing pin in johnny-five - set sampling freq to 1 ms, still see ~10ms latencies that are highly variable