firefox addon - Convert array of byte values to base64 encoded string and break long lines, Javascript (code golf)

Question

This JavaScript function takes an array of numbers (in the range 0-255) and converts to a base64-encoded string, then breaks long lines if necessary:

function encode(data)
{
  var str = "";
  for (var i = 0; i < data.length; i++)
    str += String.fromCharCode(data[i]);

  return btoa(str).split(/(.{75})/).join("
").replace(/
+/g, "
").trim();
}

Can you do the same thing in less code? Can you do it so it runs faster? Portability no object, use brand new language features if you want, but 's gotta be in JavaScript.

Answer 1

I have another entry:

function encode(data)
{
    var str = String.fromCharCode.apply(null,data);
    return btoa(str).replace(/.{76}(?=.)/g,'$&
');
}

Minified, 88 characters:

function e(d){return btoa(String.fromCharCode.apply(d,d)).replace(/.{76}(?=.)/g,'$&
')}

Or if you want trailing newlines, 85 characters:

function e(d){return btoa(String.fromCharCode.apply(d,d)).replace(/.{1,76}/g,'$&
')}