serial.pipe

Here's my code using pipe:

/* Module for interfacing with FrSky SBUS radio control receivers

Serial2.setup(100000, {rx:A3,parity:E,stopbits:2});
mysbus = require('SBUS').connect(Serial2, function(data){
  console.log(data);
});

*/

function decode(frame, callback) {
  arr = E.toUint8Array(frame);
  callback({
    ch1 :  ((arr[0]     | arr[1]<<8)                & 0x07FF),
    ch2 :  ((arr[1]>>3  | arr[2]<<5)                & 0x07FF),
    ch3 :  ((arr[2]>>6  | arr[3]<<2  | arr[4]<<10)  & 0x07FF),
    ch4 :  ((arr[4]>>1  | arr[5]<<7)                & 0x07FF),
    ch5 :  ((arr[5]>>4  | arr[6]<<4)                & 0x07FF),
    ch6 :  ((arr[6]>>7  | arr[7]<<1  | arr[8]<<9)   & 0x07FF),
    ch7 :  ((arr[8]>>2  | arr[9]<<6)                & 0x07FF),
    ch8 :  ((arr[9]>>5  | arr[10]<<3)               & 0x07FF),
    ch9 :  ((arr[11]    | arr[12]<<8)               & 0x07FF),
    ch10 : ((arr[12]>>3 | arr[13]<<5)               & 0x07FF),
    ch11 : ((arr[13]>>6 | arr[14]<<2 | arr[15]<<10) & 0x07FF),
    ch12 : ((arr[15]>>1 | arr[16]<<7)               & 0x07FF),
    ch13 : ((arr[16]>>4 | arr[17]<<4)               & 0x07FF),
    ch14 : ((arr[17]>>7 | arr[18]<<1 | arr[19]<<9)  & 0x07FF),
    ch15 : ((arr[19]>>2 | arr[20]<<6)               & 0x07FF),
    ch16 : ((arr[20]>>5 | arr[21]<<3)               & 0x07FF),
    ch18 : (arr[22] & 0x0001) ? 2047:0,
    ch19 : ((arr[22] >> 1) & 0x0001) ? 2047:0,
    framelost : ((arr[22] >> 2) & 0x0001) ? true:false,
    failsafe  : ((arr[22] >> 3) & 0x0001) ? true:false,
  });
}

exports.connect = function (serial, callback) {
  dest = {
    state: 'sync',
    last: '',
    write : function(data) {
      switch(this.state){
        case 'sync':
          buff = data;
          if (this.last === "\x00" && buff.substr(0,1) == "\x0F"){
            this.state = 'read';
          }
          break;
        case 'read':
          buff += data;
          if (buff.length > 24) {
            if (buff.substr(24,1) === "\x00") {
              this.state = 'sync';
              decode(buff.substr(1,23), callback); 
            }else{
              buff = buff.substr(buff.length - buff.indexOf("\x0F",1));
            }
          }
          break;
      }
      this.last = data.substr(-1,1);
    }
  };
  serial.pipe(dest,{chunkSize : 25});
};