How can i append file using filewritersync?

Question

I need to append file using HTML5 FileWriterSync, multiple blocks of data coming from server. I was tried to append but it was just writing a block of file only. Let's check my code.

var creator;
try {
    fileEntry = fs.root.getFile(filename, {
        create: creator
    });

    var byteArray = new Uint8Array(data.length);
    for (var i = 0; i < data.length; i++) {
        byteArray[i] = data.charCodeAt(i) & 0xff;
    }

    var BlobBuilderObj = new WebKitBlobBuilder();
    BlobBuilderObj.append(byteArray.buffer);

    if (!creator) fileEntry.createWriter().seek();
    fileEntry.createWriter().write(BlobBuilderObj.getBlob())

} catch (e) {
    errorHandler(e);
}

fs has been initialised before, creator changes for appending file and I need to append file.

My problem is how can I call seek to start writing from the EOF.

Answer 1

seek() takes an integer value for the offset. You need to set it to the file's length to do an append:

var fw = fileEntry.createWriter();
fw.seek(fw.length);

It should be similar to the async case: http://www.html5rocks.com/en/tutorials/file/filesystem/#toc-file-appending