How to append binary data to a buffer in node.js

LAST UPDATE

Use concat.

EDIT

I've written a BufferedWriter that writes bytes to a file using internal buffers. Same as BufferedReader but for writing.

A quick example:

//The BufferedWriter truncates the file because append == false
new BufferedWriter ("file")
    .on ("error", function (error){
        console.log (error);
    })

    //From the beginning of the file:
    .write ([0x00, 0x01, 0x02], 0, 3) //Writes 0x00, 0x01, 0x02
    .write (new Buffer ([0x03, 0x04]), 1, 1) //Writes 0x04
    .write (0x05) //Writes 0x05
    .close (); //Closes the writer. A flush is implicitly done.

//The BufferedWriter appends content to the end of the file because append == true
new BufferedWriter ("file", true)
    .on ("error", function (error){
        console.log (error);
    })

    //From the end of the file:
    .write (0xFF) //Writes 0xFF
    .close (); //Closes the writer. A flush is implicitly done.

//The file contains: 0x00, 0x01, 0x02, 0x04, 0x05, 0xFF

ORIGINAL QUESTION

I have a buffer with some binary data:

var b = new Buffer ([0x00, 0x01, 0x02]);

and I want to append 0x03.

How can I append more binary data? I'm searching in the documentation but for appending data it must be a string, if not, an error occurs (TypeError: Argument must be a string):

var b = new Buffer (256);
b.write ("hola");
console.log (b.toString ("utf8", 0, 4)); //hola
b.write (", adios", 4);
console.log (b.toString ("utf8", 0, 11)); //hola, adios

Then, the only solution I can see here is to create a new buffer for every appended binary data and copy it to the major buffer with the correct offset:

var b = new Buffer (4); //4 for having a nice printed buffer, but the size will be 16KB
new Buffer ([0x00, 0x01, 0x02]).copy (b);
console.log (b); //<Buffer 00 01 02 00>
new Buffer ([0x03]).copy (b, 3);
console.log (b); //<Buffer 00 01 02 03>

But this seems a bit inefficient because I have to instantiate a new buffer for every append.

Do you know a better way for appending binary data?

Sorry for my bad english.