blocks|key|698306|text|“从ArrayBuffer到Buffer”可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|698307|var+buffer+=+Buffer.from(+new+Uint8Array(ab)+);|code-block|syntax|javascript|698308|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

"From ArrayBuffer to Buffer" could be done this way: 

<pre><code>var buffer = Buffer.from( new Uint8Array(ab) );
</code></pre>

blocks|key|482457|text|一种更快的方式来编写它|type|unstyled|depth|inlineStyleRanges|entityRanges|data|482458|var+arrayBuffer+=+new+Uint8Array(nodeBuffer).buffer;|code-block|syntax|javascript|482459|然而，这似乎比在具有1024个元素的缓冲区上建议的toArrayBuffer函数的运行速度慢大约4倍。|482460|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

A quicker way to write it

<pre><code>var arrayBuffer = new Uint8Array(nodeBuffer).buffer;
</code></pre>

However, this appears to run roughly 4 times slower than the suggested toArrayBuffer function on a buffer with 1024 elements.

blocks|key|482510|text|使用下面这个优秀的npm包：to-arraybuffer。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|482511|或者，您可以自己实现它。如果您的缓冲区名为buf，请执行以下操作：|482512|buf.buffer.slice(buf.byteOffset,+buf.byteOffset+%2B+buf.byteLength)|code-block|syntax|javascript|482513|entityMap|0|LINK|mutability|MUTABLE|url|https://www.npmjs.com/package/to-arraybuffer^0|E|E|E|E|0|0|L|3|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@$9|X|A|Y|1|Z]]|E|$]]|$1|F|3|G|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|13|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

Use the following excellent npm package: <a href="https://www.npmjs.com/package/to-arraybuffer" rel="noreferrer"><code>to-arraybuffer</code></a>.

Or, you can implement it yourself. If your buffer is called <code>buf</code>, do this:

<pre><code>buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength)
</code></pre>

blocks|key|698583|text|Buffer是ArrayBuffer的view。您可以使用buffer属性获得内部包装的ArrayBuffer。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|698584|这是共享内存，不需要复制。|698585|const+arrayBuffer+=+theBuffer.buffer|code-block|syntax|javascript|698586|如果需要数据的copy，请从原始Buffer+(而不是从包装的ArrayBuffer)创建另一个Buffer，然后引用它的包装的ArrayBuffer。|698587|const+newArrayBuffer+=+Buffer.from(theBuffer).buffer|698588|作为参考，反过来，从ArrayBuffer到Buffer|698589|const+arrayBuffer+=+getArrayBuffer()
const+sharedBuffer+=+Buffer.from(arrayBuffer)

const+copiedBuffer+=+Buffer.from(sharedBuffer)
const+copiedArrayBuffer+=+copiedBuffer.buffer|698590|entityMap^0|0|6|7|B|J|4|T|6|18|B|0|0|0|7|4|G|6|1C|6|1S|B|0|0|A|B|M|6|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|17|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|19|8|@$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]|$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|1I|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|1J|8|@$9|1K|A|1L|B|C]|$9|1M|A|1N|B|C]]|D|@]|E|$]]|$1|S|3|T|5|J|7|1O|8|@]|D|@]|E|$K|L]]|$1|U|3|-4|5|6|7|1P|8|@]|D|@]|E|$]]]|V|$]]

A <code>Buffer</code> is a <code>view</code> for an <code>ArrayBuffer</code>. You can get to the internal wrapped <code>ArrayBuffer</code> using the <code>buffer</code> property.
This is shared memory, and no copying is required.
<pre class="lang-js prettyprint-override"><code>const arrayBuffer = theBuffer.buffer
</code></pre>
If you want a <code>copy</code> of the data, create another <code>Buffer</code> from the original <code>Buffer</code> (NOT from the wrapped ArrayBuffer), and then reference its wrapped <code>ArrayBuffer</code>.
<pre class="lang-js prettyprint-override"><code>const newArrayBuffer = Buffer.from(theBuffer).buffer
</code></pre>
For reference, going the other direction, from an <code>ArrayBuffer</code> to a <code>Buffer</code>
<pre class="lang-js prettyprint-override"><code>const arrayBuffer = getArrayBuffer()
const sharedBuffer = Buffer.from(arrayBuffer)

const copiedBuffer = Buffer.from(sharedBuffer)
const copiedArrayBuffer = copiedBuffer.buffer
</code></pre>

blocks|key|482540|text|我尝试了上面的Float64Array，它就是不能工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|482541|我最终意识到，数据确实需要以正确的块“读入”视图。这意味着一次从源缓冲区读取8个字节。|482542|不管怎么说，这就是我最终得到的。|482543|var+buff+=+new+Buffer("40100000000000004014000000000000",+"hex");
var+ab+=+new+ArrayBuffer(buff.length);
var+view+=+new+Float64Array(ab);

var+viewIndex+=+0;
for+(var+bufferIndex=0;bufferIndex<buff.length;bufferIndex=bufferIndex%2B8)++++++++++++{

++++view[viewIndex]+=+buff.readDoubleLE(bufferIndex);
++++viewIndex%2B%2B;
}|code-block|syntax|javascript|482544|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I tried the above for a Float64Array and it just did not work.

I ended up realising that really the data needed to be read 'INTO' the view in correct chunks. This means reading 8 bytes at a time from the source Buffer.

Anyway this is what I ended up with...

<pre><code>var buff = new Buffer("40100000000000004014000000000000", "hex");
var ab = new ArrayBuffer(buff.length);
var view = new Float64Array(ab);

var viewIndex = 0;
for (var bufferIndex=0;bufferIndex&lt;buff.length;bufferIndex=bufferIndex+8) {

 view[viewIndex] = buff.readDoubleLE(bufferIndex);
 viewIndex++;
}
</code></pre>

blocks|key|482654|text|此代理将缓冲区公开为任何TypedArrays，而不复制任何副本。：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|482655|https://www.npmjs.com/package/node-buffer-as-typedarray|offset|length|482656|它只在LE上工作，但可以很容易地移植到LE上。而且，从来没有真正测试过它的效率。|482657|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|1J|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@$D|Q|E|R|1|S]]|A|$]]|$1|F|3|G|5|6|7|T|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|U|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|C]]]]

This Proxy will expose the buffer as any of the TypedArrays, without any copy. : 

<a href="https://www.npmjs.com/package/node-buffer-as-typedarray" rel="nofollow noreferrer">https://www.npmjs.com/package/node-buffer-as-typedarray</a>

It only works on LE, but can be easily ported to BE.
Also, never got to actually test how efficient this is.

blocks|key|482355|text|NodeJS一度(我认为是v0.6.x)支持ArrayBuffer。我创建了一个用于对here进行base64编码和解码的小型库，但由于更新到了v0.7，(在NodeJS上)测试失败。我正在考虑创建一些东西来规范化这一点，但在此之前，我认为应该使用Node的原生Buffer。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|482356|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/arunjitsingh/base64^0|3N|6|17|4|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

NodeJS, at one point (I think it was v0.6.x) had ArrayBuffer support. I created a small library for base64 encoding and decoding <a href="https://github.com/arunjitsingh/base64" rel="nofollow">here</a>, but since updating to v0.7, the tests (on NodeJS) fail. I'm thinking of creating something that normalizes this, but till then, I suppose Node's native <code>Buffer</code> should be used.

blocks|key|698485|text|我已经将我的节点更新到版本5.0.0，并且我使用下面的代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|698486|function+toArrayBuffer(buffer){
++++var+array+=+[];
++++var+json+=+buffer.toJSON();
++++var+list+=+json.data

++++for(var+key+in+list){
++++++++array.push(fixcode(list[key].toString(16)))
++++}

++++function+fixcode(key){
++++++++if(key.length==1){
++++++++++++return+'0'%2Bkey.toUpperCase()
++++++++}else{
++++++++++++return+key.toUpperCase()
++++++++}
++++}

++++return+array
}|code-block|syntax|javascript|698487|我用它来检查我的vhd磁盘映像。|698488|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I have already update my node to Version 5.0.0
And I work work with this:

<pre><code>function toArrayBuffer(buffer){
 var array = [];
 var json = buffer.toJSON();
 var list = json.data

 for(var key in list){
 array.push(fixcode(list[key].toString(16)))
 }

 function fixcode(key){
 if(key.length==1){
 return '0'+key.toUpperCase()
 }else{
 return key.toUpperCase()
 }
 }

 return array
}
</code></pre>

I use it to check my vhd disk image.

How can I convert a NodeJS binary buffer into a JavaScript ArrayBuffer?

Convert a binary NodeJS Buffer to JavaScript ArrayBuffer

如何将NodeJS二进制缓冲区转换为JavaScript ArrayBuffer？

问将二进制NodeJS缓冲区转换为JavaScript ArrayBuffer
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