字符串的ArrayBuffer，ArrayBuffer方法的字符串

Question

这个问题过去已有答案，但我可以肯定地说，至今仍未获得答案。

关于ArrayBuffers的文档几乎都是大体的，更不用说具体的应用程序了。我已经研究了几天，但对此一无所获。

本质上，我需要尝试将从文件读取器(此处：https://developer.mozilla.org/en-US/docs/Web/API/FileReader/readAsArrayBuffer)获得的ArrayBuffer转换为字符串，然后将该字符串转换回相同的ArrayBuffer。

我已经尝试过这些方法，例如

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 b

我得到以下错误：“Uint16Array的字节长度应该是2的倍数”

我还尝试了以下方法

function StringToUint8Array(string) {
    var binary, binLen, buffer, chars, i, _i;
    binary = StringToBinary(string);
    binLen = binary.length;
    buffer = new ArrayBuffer(binLen);
    chars  = new Uint8Array(buffer);
    for (i = _i = 0; 0 <= binLen ? _i < binLen : _i > binLen; i = 0 <= binLen ? ++_i : --_i) {
        chars[i] = String.prototype.charCodeAt.call(binary, i);
    }
    return chars;
}

function ArrayBufferToString(buffer) {
    return BinaryToString(String.fromCharCode.apply(null, Array.prototype.slice.apply(new Uint8Array(buffer))));
}

function StringToArrayBuffer(string) {
    return StringToUint8Array(string).buffer;
}

function BinaryToString(binary) {
    var error;

    try {
        return decodeURIComponent(escape(binary));
    } catch (_error) {
        error = _error;
        if (error instanceof URIError) {
            return binary;
        } else {
            throw error;
        }
    }
}

function StringToBinary(string) {
    var chars, code, i, isUCS2, len, _i;

    len = string.length;
    chars = [];
    isUCS2 = false;
    for (i = _i = 0; 0 <= len ? _i < len : _i > len; i = 0 <= len ? ++_i : --_i) {
        code = String.prototype.charCodeAt.call(string, i);
        if (code > 255) {
            isUCS2 = true;
            chars = null;
            break;
        } else {
            chars.push(code);
        }
    }
    if (isUCS2 === true) {
        return unescape(encodeURIComponent(string));
    } else {
        return String.fromCharCode.apply(null, Array.prototype.slice.apply(chars));
    }
}

并收到此错误:已超过最大调用堆栈大小

似乎没有好的方法来进行以下转换: AB --> String || String -> AB

Answer 1

有一种使用Blob和FileReader的异步方式。

您可以指定任何有效的编码。

function arrayBufferToString( buffer, encoding, callback ) {
    var blob = new Blob([buffer],{type:'text/plain'});
    var reader = new FileReader();
    reader.onload = function(evt){callback(evt.target.result);};
    reader.readAsText(blob, encoding);
}

function stringToArrayBuffer( string, encoding, callback ) {
    var blob = new Blob([string],{type:'text/plain;charset='+encoding});
    var reader = new FileReader();
    reader.onload = function(evt){callback(evt.target.result);};
    reader.readAsArrayBuffer(blob);
}


//example:
var buf = new Uint8Array([65,66,67]);
arrayBufferToString(buf, 'UTF-8', console.log.bind(console)); //"ABC"

stringToArrayBuffer('ABC', 'UTF-8', console.log.bind(console)); //[65,66,67]

Answer 2

现在大多数浏览器都有TextEncoder和TextDecoder，Node有util.TextEncoder和util.TextDecoder。这个WHATWG标准提供了在字节数组(具有buffer属性)和字符串之间进行转换的简单方法：

const str = new TextDecoder().decode(byteArray);
const byteArray = new TextEncoder().encode(str);
const buffer = byteArray.buffer;

Answer 3

下面是转换函数的TypeScript版本，通过cuixping来补充这个出色的答案

const arrayBufferToString = (buffer: ArrayBuffer, encoding = 'UTF-8'): Promise<string> => {
  return new Promise<string>((resolve, reject) => {
    const blob = new Blob([buffer], { type: 'text/plain' });
    const reader = new FileReader();
    reader.onload = (evt) => {
      if (evt.target) {
        resolve(evt.target.result as string);
      } else {
        reject(new Error('Could not convert array to string!'));
      }
    };
    reader.readAsText(blob, encoding);
  });
};

const stringToArrayBuffer = (text: string, encoding = 'UTF-8'): Promise<ArrayBuffer> => {
  return new Promise<ArrayBuffer>((resolve, reject) => {
    const blob = new Blob([text], { type: `text/plain;charset=${encoding}` });
    const reader = new FileReader();
    reader.onload = (evt) => {
      if (evt.target) {
        resolve(evt.target.result as ArrayBuffer);
      } else {
        reject(new Error('Could not convert string to array!'));
      }
    };
    reader.readAsArrayBuffer(blob);
  });
};