WARNING: jsvGetString overflowed

Clock = require("clock").Clock;

clk=new Clock("Thu, 17 Sep 2015 23:35:52");

  systemStatus={
    light:{
      clear:-1,
      red:-1,
      green:-1,
      blue:-1
    },
    temperature:-1,
    pressure: -1,
    RFDevs:[0,0,0],
    door_upstairs:0,
    door_downstairs:0,
    fridge:0,
    lastMotion:0,
    fargo:new Uint8Array(8)
  };

function getMirrorString() {
  var s=systemStatus;
  var tstr="?door_up="+s.door_upstairs+"&door_­down="+s.door_downstairs+"&fridge="+s.fr­idge;
  tstr+=(s.light.clear>=0?"&clear="+s.ligh­t.clear+"&red="+s.light.red+"&green="+s.­light.green+"&blue="+s.light.blue:"");
  tstr+=(s.pressure>0?"&pressure="+s.press­ure:"")+"&LastMove="+safeGetTime()-s.las­tMotion;
}

function safeGetTime(){
  if (clk) {
    return clk.getDate().getTime();
  } else {
    return -1;
  }
}

 _____                 _
|   __|___ ___ ___ _ _|_|___ ___
|   __|_ -| . |  _| | | |   | . |
|_____|___|  _|_| |___|_|_|_|___|
          |_| http://espruino.com
 1v80.334 Copyright 2015 G.Williams
>echo(0);
=undefined
>getMirrorString()
WARNING: jsvGetString overflowed
=undefined
>