使用Javascript将文件拆分为块 [英] Splitting a File into Chunks with Javascript

问题描述

我正在尝试获取单个文件对象，并按指定的块大小将其拆分为块。
在我的示例中，尝试将单个文件拆分为1MB块。所以我想出它需要多少块，然后我试图从'offset'开始切片文件（当前块我在*块大小上），并切掉一个块大小。
我的第一个切片正确地以1MB出现，但随后的切片变成0，任何想法为什么？
这里有一个有效的代码：

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:

http://codepen.io/ngalluzzo/pen/VvpYKz?editors=001 [1]

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 <= 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++;
  }

推荐答案

正在切断错误的目的：

console.log(file.slice(offset,chunkSize));

应该是

console.log(file.slice(offset,offset+chunkSize));

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