I have a query regarding file operations using JavaScript-

Scenario - My JS function calls a wcf service which returns the file content in the form of byte array or stream and the mime type. This byte array/stream needs to be converted to a file and which will be downloaded on user's machine.
Reference code -

var arr = "This is test content";
var byteArray = new Uint8Array(arr);
var a = window.document.createElement('a');

a.href = window.URL.createObjectURL(new Blob([byteArray], {
    type: 'text/plain'
}));
a.download = "Test";

document.body.appendChild(a);
a.click();

document.body.removeChild(a);

The code works for only text files. Files with mime type other than text are corrupted. I understand that file operations are severly restricted at client side, but just to confirm - Is there anyway to convert byte array/stream to files such as Word,Excel, PDF and etc ?

I have a query regarding file operations using JavaScript-

Scenario - My JS function calls a wcf service which returns the file content in the form of byte array or stream and the mime type. This byte array/stream needs to be converted to a file and which will be downloaded on user's machine.
Reference code -

var arr = "This is test content";
var byteArray = new Uint8Array(arr);
var a = window.document.createElement('a');

a.href = window.URL.createObjectURL(new Blob([byteArray], {
    type: 'text/plain'
}));
a.download = "Test";

document.body.appendChild(a);
a.click();

document.body.removeChild(a);

The code works for only text files. Files with mime type other than text are corrupted. I understand that file operations are severly restricted at client side, but just to confirm - Is there anyway to convert byte array/stream to files such as Word,Excel, PDF and etc ?

• javascript
• wcf

Share Improve this question Follow edited May 23, 2017 at 11:53 CommunityBot 111 silver badge asked Oct 14, 2015 at 11:24 Thomas MathewThomas Mathew 1,15166 gold badges1515 silver badges3030 bronze badges 3

• Similar question here: stackoverflow./questions/27946228/… – Akhoy Commented Oct 14, 2015 at 12:38
• @Akhoy Thanks. Same URL as the reference code. As i said, text files are working but not word or pdf. – Thomas Mathew Commented Oct 15, 2015 at 3:41
• How to do this on .NET C#? I need to convert a File MIMEType octet-stream (format bytestream) to a excel is it possible too? – AbbathCL Commented Aug 26, 2021 at 23:26

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1 Answer 1

Sorted by: Reset to default 2

I acplish a similar goal with this. Pick up from where you have your byteArray, and try this:

    var byteArray = new Uint8Array(arrayBuffer);
    var a = window.document.createElement('a');   
    a.href = window.URL.createObjectURL(new Blob([byteArray], { type:'application/octet-stream' }));

    // supply your own fileName here...
    a.download = "YourFileName.XLSX";

    document.body.appendChild(a)
    a.click();
    document.body.removeChild(a)

Setting contentType to "application/octet-stream" will acmodate any binary file type.