Scroll String on 3 x 8x8 neopixel panel

scrollString.js

// scrollString.js
// tested on ESP8266 12F 
var pin = D4;

// connected to three neopixel plate (x,y)=(0-7,0-23)
var leds = Graphics.createArrayBuffer(8,24,24);
leds.setRotation(1,false);

leds.flip = function(){require("neopixel").write(pin,leds.buffer);};
leds.off = function(){leds.clear();leds.flip();};

// right to left
function scrollString(scroll) {
  if ( !scroll.active ) {
    clearTimeout(timer);
    leds.off();
  }
  else {
    if ( scroll.xpos !== -1*scroll.len ) {
      timer=setTimeout(function(scroll){scrollString(scroll);},scroll.delay_scroll,scroll);
      leds.clear();
      leds.setColor(scroll.color.blue,scroll.color.red,scroll.color.green);
      leds.drawString(scroll.text,scroll.xpos,scroll.ypos);
      // setTimeout('leds.flip();',scroll.delay_flip);
      leds.flip();
      scroll.xpos--; 
    }
    else {
      scroll.xpos=leds.getWidth();
      scrollString(scroll);
    }
  }
}

var s1 = {
  text  : "Espruino rocks",
  len  : 56,                // using 4x6font
  xpos  : leds.getWidth(),  // offset x
  ypos  : 1,                // ofset y
  delay_scroll : 300,       // time delay for scroll
  color  : { red:0,green:0.2,blue:0.2},
  active : true,            // false will stop scrolling
};

leds.off();
leds.setColor(0,0,0);
scrollString(s1);