是否有一种普遍接受的技术可以有效地将JavaScript字符串转换为arraybuffer,反之亦然?具体来说,我希望能够将ArrayBuffer的内容写入localStorage,然后再将其读回来。


当前回答

  stringToArrayBuffer(byteString) {
    var byteArray = new Uint8Array(byteString.length);
    for (var i = 0; i < byteString.length; i++) {
      byteArray[i] = byteString.codePointAt(i);
    }
    return byteArray;
  }
  arrayBufferToString(buffer) {
    var byteArray = new Uint8Array(buffer);
    var byteString = '';
    for (var i = 0; i < byteArray.byteLength; i++) {
      byteString += String.fromCodePoint(byteArray[i]);
    }
    return byteString;
  }

其他回答

如果你使用的是巨型数组,例如arr.length=1000000 您可以使用此代码来避免堆栈回调问题

function ab2str(buf) {
var bufView = new Uint16Array(buf);
var unis =""
for (var i = 0; i < bufView.length; i++) {
    unis=unis+String.fromCharCode(bufView[i]);
}
return unis
}

逆函数 Mangini从上面回答

function str2ab(str) {
    var buf = new ArrayBuffer(str.length*2); // 2 bytes for each char
    var bufView = new Uint16Array(buf);
    for (var i=0, strLen=str.length; i<strLen; i++) {
        bufView[i] = str.charCodeAt(i);
    }
    return buf;
}
  stringToArrayBuffer(byteString) {
    var byteArray = new Uint8Array(byteString.length);
    for (var i = 0; i < byteString.length; i++) {
      byteArray[i] = byteString.codePointAt(i);
    }
    return byteArray;
  }
  arrayBufferToString(buffer) {
    var byteArray = new Uint8Array(buffer);
    var byteString = '';
    for (var i = 0; i < byteArray.byteLength; i++) {
      byteString += String.fromCodePoint(byteArray[i]);
    }
    return byteString;
  }

假设你有一个arrayBuffer binaryStr:

let text = String.fromCharCode.apply(null, new Uint8Array(binaryStr));

然后你把文本赋值给状态。

我发现这种方法有问题,主要是因为我试图将输出写入一个文件,而它没有正确编码。由于JS似乎使用UCS-2编码(源,源),我们需要进一步扩展这个解决方案,这是我的增强解决方案,对我来说是有效的。

我对一般文本没有任何困难,但当它变成阿拉伯语或韩语时,输出文件没有所有字符,而是显示错误字符

文件输出: ”、“单位”:“10 K”:“O©iuY喜爱”、“遵循% % {screen_name} {screen_name}”:“U”“O©iu“推特:“¤问题”、“推%{标签}”:“%{标签}’一个¤uEY喜爱”,“推特%{名称}”:“%{名称}U”xA¤uEY喜爱”},柯:{“% {followers_count}的追随者”:“% {followers_count}…X \”,“100 K +”:“100我助教”,“10 K单位”:“我e”,遵循:“\°”,“跟着% {screen_name}”:“% {screen_name}Ø\°X0”,凯西:“œ”,男:“我”,推特:“¸”,“推特%{标签}”:“%{标签}

original: ", " 10 k unit ": "万",follow: "关注"," follow百分之百分之;screen _ name} ": " {screen _ name}先生圆场,tweet: "推特"," tweet百分之百分之{hashtag} ": " {hashtag},推特的"," tweet to百分之百分之{name} ": " {name}先生推到百分之":{},ko " {followers _ count}百分之followers ": " {followers _ count}명의팔로워100 k + ": " 100 ", "만이상"," 10 k unit ": "만단위",follow: "팔로우"," follow百分之百分之{screen _ name} ": " {screen _ name}님팔로우하기",k: "천",米:"백만",tweet: "트윗"," tweet百分之百分之{hashtag} ": " {hashtag}

我从dennis的解决方案和我发现的这个帖子中获取了信息。

这是我的代码:

function encode_utf8(s) {
  return unescape(encodeURIComponent(s));
}

function decode_utf8(s) {
  return decodeURIComponent(escape(s));
}

 function ab2str(buf) {
   var s = String.fromCharCode.apply(null, new Uint8Array(buf));
   return decode_utf8(decode_utf8(s))
 }

function str2ab(str) {
   var s = encode_utf8(str)
   var buf = new ArrayBuffer(s.length); 
   var bufView = new Uint8Array(buf);
   for (var i=0, strLen=s.length; i<strLen; i++) {
     bufView[i] = s.charCodeAt(i);
   }
   return bufView;
 }

这允许我将内容保存到一个文件,而没有编码问题。

How it works: It basically takes the single 8-byte chunks composing a UTF-8 character and saves them as single characters (therefore an UTF-8 character built in this way, could be composed by 1-4 of these characters). UTF-8 encodes characters in a format that variates from 1 to 4 bytes in length. What we do here is encoding the sting in an URI component and then take this component and translate it in the corresponding 8 byte character. In this way we don't lose the information given by UTF8 characters that are more than 1 byte long.

尽管Dennis和gengkev使用Blob/FileReader的解决方案有效,但我不建议采用这种方法。这是一种解决简单问题的异步方法,比直接解决方案要慢得多。我在html5rocks上发布了一个更简单(更快)的解决方案: http://updates.html5rocks.com/2012/06/How-to-convert-ArrayBuffer-to-and-from-String

解决方案是:

function ab2str(buf) {
  return String.fromCharCode.apply(null, new Uint16Array(buf));
}

function str2ab(str) {
  var buf = new ArrayBuffer(str.length*2); // 2 bytes for each char
  var bufView = new Uint16Array(buf);
  for (var i=0, strLen=str.length; i<strLen; i++) {
    bufView[i] = str.charCodeAt(i);
  }
  return buf;
}

编辑:

Encoding API帮助解决字符串转换问题。请查看Jeff Posnik在Html5Rocks.com上对上述原创文章的回复。

摘录:

Encoding API使原始字节和原生JavaScript字符串之间的转换变得简单,而不考虑需要使用的许多标准编码中的哪一种。

<pre id="results"></pre>

<script>
  if ('TextDecoder' in window) {
    // The local files to be fetched, mapped to the encoding that they're using.
    var filesToEncoding = {
      'utf8.bin': 'utf-8',
      'utf16le.bin': 'utf-16le',
      'macintosh.bin': 'macintosh'
    };

    Object.keys(filesToEncoding).forEach(function(file) {
      fetchAndDecode(file, filesToEncoding[file]);
    });
  } else {
    document.querySelector('#results').textContent = 'Your browser does not support the Encoding API.'
  }

  // Use XHR to fetch `file` and interpret its contents as being encoded with `encoding`.
  function fetchAndDecode(file, encoding) {
    var xhr = new XMLHttpRequest();
    xhr.open('GET', file);
    // Using 'arraybuffer' as the responseType ensures that the raw data is returned,
    // rather than letting XMLHttpRequest decode the data first.
    xhr.responseType = 'arraybuffer';
    xhr.onload = function() {
      if (this.status == 200) {
        // The decode() method takes a DataView as a parameter, which is a wrapper on top of the ArrayBuffer.
        var dataView = new DataView(this.response);
        // The TextDecoder interface is documented at http://encoding.spec.whatwg.org/#interface-textdecoder
        var decoder = new TextDecoder(encoding);
        var decodedString = decoder.decode(dataView);
        // Add the decoded file's text to the <pre> element on the page.
        document.querySelector('#results').textContent += decodedString + '\n';
      } else {
        console.error('Error while requesting', file, this);
      }
    };
    xhr.send();
  }
</script>