Get/set file encoding with javascript's FileReader

Question

I am struggling with the following problem. Using javascript I would like to change the character set of a file content and display this content to the user.

I have

Answer 1

If your HTML page is in UTF-8 and your file is in ISO-8859-1.

This is working:

 reader.readAsText(file, 'ISO-8859-1');

I don't have any Windows-1251 file so I was not able to test it but it looks like that the 'CP1251' is supported (by Google Chrome at least), so:

 reader.readAsText(file, 'CP1251');

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If none of this is working. Then you should change the formatting manually. Unfortunately, I am not aware of any JavaScript library that does the trick.

From the unicode mapping here and from Delan Azabani answer, you should manage to build a function that convert char by char your string in CP1251 to UTF-8.