将 Javascript BLOB 编码更改为 ANSI 而不是 UTF-8

Question

我想知道是否可以使用 Javascript 和 ANSI 编码的 BLOB 保存一个简单的 txt 文件。

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目前，我有一个脚本创建一个带有 CRLF 行结尾但采用 UTF-8 编码的 txt 文件。

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可以用ANSI编码保存吗？我需要这个来导入需要 ANSI 而不是 UTF-8 的“旧”Windows 程序上的 txt 文件。

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这是我使用的示例：\n https://jsfiddle.net/UselessCode/qm5AG/

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let textFile = null;\n\nfunction makeTextFile () {\n    let text = `Some text with nice line endings\\nand special characters like \xc3\xa9 and \xc3\xbc.`;\n\n    const data = new Blob([text], {\n        type: "text/plain",\n        endings: "native"\n    });\n\n    if (textFile !== null) {\n        window.URL.revokeObjectURL(textFile);\n    }\n\n    textFile = window.URL.createObjectURL(data);\n\n    return textFile;\n}\n

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Answer 1

曾经有一个选项使用TextEncoder API将 USVString 编码为任意编码，但这已从规范和浏览器中删除。

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您需要使用库才能执行转换。在这里，我将使用inexorabletash/text-encoding：

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(async()=> {\r\nconst text = `Some text with nice line endings\\nand special characters like \xc3\xa9 and \xc3\xbc.`;\r\nconst encoding = \'windows-1252\'; // a.k.a ANSI\r\n\r\nconst encoder = new TextEncoder(encoding, {\r\n  NONSTANDARD_allowLegacyEncoding: true\r\n});\r\nconst data = encoder.encode(text); // `data` is an Uint8Array\r\nconst encoded_as_ANSI = new Blob([data]);\r\n\r\n// for demo only\r\nconst encoded_as_UTF8 = new Blob([text]);\r\n\r\nconst ANSI_read = await readAsText(encoded_as_ANSI, encoding);\r\nconst UTF8_read = await readAsText(encoded_as_UTF8, encoding);\r\n\r\nconsole.log("(ANSI)", ANSI_read);\r\nconsole.log("(UTF8)", UTF8_read);\r\n})();\r\n\r\nfunction readAsText(blob, encoding) {\r\n  return new Promise(res => {\r\n    const reader = new FileReader();\r\n    reader.onload = e => res(reader.result);\r\n    reader.readAsText(blob, encoding);\r\n  });\r\n}

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<script>window.TextEncoder = null;// force installation of the polyfill</script>\r\n<script src="https://cdn.jsdelivr.net/gh/inexorabletash/text-encoding/lib/encoding-indexes.js"></script>\r\n<script src="https://cdn.jsdelivr.net/gh/inexorabletash/text-encoding/lib/encoding.js"></script>

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然而，按照这条路线，我们失去了结尾选项，因为这仅适用于字符串 blobParts。

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因此，一种方法是首先创建一个带有结尾选项的 utf-8 Blob，然后将此 UTF-8 Blob 转换为 ANSI：

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(async () => {\r\n  const text = `Some text with nice line endings\\nand special characters like \xc3\xa9 and \xc3\xbc.`;\r\n  const encoding = \'windows-1252\'; // a.k.a ANSI\r\n\r\n  const utf8_blob = new Blob( [text], { endings: "native" } );\r\n  const utf_8_txt = await utf8_blob.text();\r\n\r\n  const encoder = new TextEncoder(encoding, {\r\n    NONSTANDARD_allowLegacyEncoding: true\r\n  });\r\n  const data = encoder.encode(utf_8_txt); // now `data` is an Uint8Array\r\n  const encoded_as_ANSI = new Blob([data]);\r\n\r\n  const read_as_ANSI = await readAsText(encoded_as_ANSI, encoding)\r\n  console.log(read_as_ANSI);\r\n})();\r\n\r\nfunction readAsText(blob, encoding) {\r\n  return new Promise(res => {\r\n    const reader = new FileReader();\r\n    reader.onload = e => res(reader.result);\r\n    reader.readAsText(blob, encoding);\r\n  });\r\n}

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<script>window.TextEncoder = null;// force installation of the polyfill</script>\r\n<script src="https://cdn.jsdelivr.net/gh/inexorabletash/text-encoding/lib/encoding-indexes.js"></script>\r\n<script src="https://cdn.jsdelivr.net/gh/inexorabletash/text-encoding/lib/encoding.js"></script>

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