title: Splitting a File into Chunks with Javascript
body: <p>I'm trying to take a single file object and split it into chunks by a specified chunk size.
  In my example, trying to split a single file into 1MB chunks. So I figure out how many chunks it would take, then I'm trying to slice the file starting from the 'offset' (current chunk I'm on * chunk size), and slicing off a chunk size.
  My first slice comes out properly at 1MB but my subsequent slices turn out to 0, any ideas why?
  Have a working codepen here: </p>
  
  <p><a href="http://codepen.io/ngalluzzo/pen/VvpYKz?editors=001[1]" rel="noreferrer">http://codepen.io/ngalluzzo/pen/VvpYKz?editors=001[1]</a></p>
  
  <pre><code>var file = $('#uploadFile')[0].files[0];
    var chunkSize = 1024 * 1024;
    var fileSize = file.size;
    var chunks = Math.ceil(file.size/chunkSize,chunkSize);
    var chunk = 0;
  
    console.log('file size..',fileSize);
    console.log('chunks...',chunks);
  
    while (chunk &lt;= chunks) {
        var offset = chunk*chunkSize;
        console.log('current chunk..', chunk);
        console.log('offset...', chunk*chunkSize);
        console.log('file blob from offset...', offset)
        console.log(file.slice(offset,chunkSize));
        chunk++;
    }
  </code></pre>