javascript - 下载文件时设置csv编码

Question

我正在使用react、Paparse和encoding-japanese

使用 Paparse，我可以上传 CSV 并从 Shift-JS 对其进行解码。但库不支持相反的操作。

我添加了encoding-japanese，以便将字符串转换为SHIFT-js并下载。

这是我的代码:

    const csv = csvParser.unparse({
        "fields": ["行形式","取引番号","取引日","支払期限","顧客番号","顧客企業名","顧客電話番号","送付先郵便番号","請求書発行日","郵送","メール送付","取引金額","明細","単価","数量","金額","消費税率","税込対象額_10%","税込対象額_8%","税込対象額_経8%","税込対象額_旧8%","税込対象額_非","税込対象額_対象外"],
        "data": [
            ["取引","transaction-20200218-094750_1","2020/02/18","2020/03/31","DP79","Sample1Corp","03-0000-0000","123-4567","2020/02/19","0","1","110","","","","","","110","","","",""]
        ]
    });
    const a = document.createElement("a");
    const sjisArray = Encoding.convert(csv, 'SJIS', 'UTF8');
    console.log(sjisArray)
    a.href = window.URL.createObjectURL(new Blob(['\ufeff'+sjisArray], {type: "text/csv;charset=shift-js"}));
    a.download = "取引サンプル.csv";
    a.click();

它没有抛出任何错误，但是当我在记事本中打开我的 csv 文件时，它仍然是带 BOM 的 UTF8 格式。

我希望将它放在 shift-js 中。

我怎样才能做到这一点？

Answer 1

您的 Encoding 库当前返回一个 DOMString，因为您传递了这样一个 DOMString 作为输入。
这意味着您的 Blob 构造函数会将此 DOMString 转换为 UTF-8，这就是您文件中的内容:Shift-JIS 编码文本的 UTF-16 表示形式的 UTF-8 版本.

至少可以说，这不是您想要的。

快速查看该库的文档，似乎最好的方法是传递文本的 ArrayBuffer 版本进行编码，以便它返回给您一个字节值数组(类似于 Uint8Array，除了它们使用正常的无论出于何种原因数组...)。

然后，您将能够从该字节数组生成一个新的 ArrayBuffer，您可以将其传递给 Blob，而无需将其转换回 UTF-8。

const csv = Papa.unparse({
    "fields": ["行形式","取引番号","取引日","支払期限","顧客番号","顧客企業名","顧客電話番号","送付先郵便番号","請求書発行日","郵送","メール送付","取引金額","明細","単価","数量","金額","消費税率","税込対象額_10%","税込対象額_8%","税込対象額_経8%","税込対象額_旧8%","税込対象額_非","税込対象額_対象外"],
    "data": [
        ["取引","transaction-20200218-094750_1","2020/02/18","2020/03/31","DP79","Sample1Corp","03-0000-0000","123-4567","2020/02/19","0","1","110","","","","","","110","","","",""]
    ]
});
// First convert our DOMString to an ArrayBuffer
const utf8Array = new TextEncoder().encode( csv );
// pass it to Encoding so we get back an Array of bytes
const sjisArray = Encoding.convert(utf8Array, 'SJIS', 'UTF8');
// now we can make our Blob without auto encoding
const blob = new Blob( [ new Uint8Array( sjisArray ) ] );

const a = document.createElement('a');
a.download = 'Shift-JIS.csv';
a.href = URL.createObjectURL( blob );
a.textContent = 'download';
document.body.append( a );
// just to check we encoded it correctly
readAsText( blob, 'Shift-JIS' )
  .then( txt => console.log( 'read back as Shift-JIS:', txt ) );
readAsText( blob, 'utf-8' )
  .then( txt => console.log( 'read back as UTF-8:', txt ) );
  
function readAsText( blob, encoding ) {
  return new Promise( (res, rej) => {
    const reader = new FileReader();
    reader.onerror = rej;
    reader.onload = (evt) => res( reader.result );
    reader.readAsText( blob, encoding );
  } );
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/PapaParse/5.1.0/papaparse.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/encoding-japanese/1.0.30/encoding.min.js"></script>