spi.send with Uint16Array

You could try:

var zzz = new Uint8Array([0,0,0]);
sData = sData.map(function() {
  var d = spi.send(zzz);
  return (((d[0]<<11) + (d[1]<<5) + d[2])*0x10001) >> 8;
});

(...*0x10001) >> 8; should swap the byte order