Javascript下载没有base64的二进制数据

Question

I want to download some binary data but Chrome forces it to utf-8 which messes up the bytes. If I set href to a data URI and use base64 encoding it works, but I want to avoid that and use a BLOB instead.

Is there a way to stop Chrome from converting this binary data to utf-8?

 const data = "\\x00\\xff\\xfe\\xe2" console.log(data) const file = new Blob([data]) const a = document.getElementById("a") const url = URL.createObjectURL(file) a.href = url; a.download = "test.txt"; 

 <a id="a">Download</a> 

In this example, you can see that my string contains the bytes

00 ff fe e2

and I convert that string to a blob. But when you download the file in Chrome and look at the bytes again you'll find

20 c3 bf c3 be c3 a2

instead. What I think is happening is that chrome takes each byte, reads it as utf-16 and converts it to utf-8. For example fe is þ when read as utf-16 but c3 be in utf-8

Answer 1

Strings are implicitly encoded as UTF-8 by the Blob constructor, so pass a typed array instead, such as Uint8Array :

 const data = "\\x00\\xff\\xfe\\xe2" console.log(data) const file = new Blob([Uint8Array.from(data, c => c.charCodeAt(0))]) const a = document.getElementById("a") const url = URL.createObjectURL(file) a.href = url; a.download = "test.txt"; 

 <a id="a">Download</a>