Quick Start

Add the following HTML Code to your head:

<script src="https://dl.dropboxusercontent.com/s/uo9kbpolhnat1cg/atobAndBtoaTogether.min.js?dl=0" type="text/javascript"></script>

If you know that no script on the page requires this library until the DOMContentLoaded event, then you can switch to the much faster (less blocking) version below:

<script defer="" src="https://dl.dropboxusercontent.com/s/uo9kbpolhnat1cg/atobAndBtoaTogether.min.js?dl=0" type="text/javascript"></script>

npm Installation

Run the following in the command line opened to the directory of your script.

npm install bestbase64utf8

Alternatively, if one do not know how to use the command line, save the script corresponding to your operating system to the directory where the nodejs script will run and use the file manager to run the script (on Windows, it's a double-click).

• Microsoft Windows batch: install-BestBase64EncoderDecoder-windows.bat
• Bash for Apple MacOS and Linux (e.x. Ubuntu): install-BestBase64EncoderDecoder-unix.sh

API Documentation

There are two separate API functions introduced by the library:

• /*String*/ btoaUTF8(/*String*/ originalString, /*boolean*/ autoBOMit = false)

  • Encodes the binary string originalString into valid base 64.
  • autoBOMit determines whether to prepend the string with a BOM. Only use this when the base64 is to be used as a data URI link. If you have no idea what this means and are confused, then simply ignore this option and it should not give you any problems.

• /*String*/ atobUTF8(/*String*/ encodedBase64String, /*boolean*/ keepBOM = false)

  • Decodes the base64 string encodedBase64String into its original UTF8 binary counterpart.
  • keepBOM will keep the BOM of the string. Set this option to true if you are certain that the original UTF8 string was raw binary data. Keep this option false if you used the autoBOMit option when encoding the string.

BestBase64EncoderDecoder

I would assume that one might want it base64 encoded in a more standard way than other solutions that attempt to address this problem. This "standard" way is naturally interpretable by the browser such that you can use the base64 in a data URI. Please visit this data URI here to see a demonstration: data:text/plain;charset=utf-8;base64,4pi44pi54pi64pi74pi84pi+4pi/ (copy the data uri, open a new tab, paste the data URI into the address bar, then press enter to go to the page). As you can see, despite the fact that it is a base64-encoded URL, the browser is still able to recognize the high code points and decode them properly. Thus, this demonstration proves that this is the best way to go because it is the most standard. Then, to decode the base64 data, either HTTP get the data as a data URI or use the atobUTF8 function. The advantage of being more standard is that this encoder and this decoder are more widely applicable because they can be used as a valid URL that displays correctly. Please visit this demo page to see the generation of unicode base64.

In addition to being very standardized, the above code snippets are also very fast. Instead of an indirect chain of succession where the data has to be converted several times between various forms, the above code snippet is as direct as performantly possible. It uses only one simple fast String.prototype.replace call to process the data when encoding, and only one to decode the data when decoding. Another plus is that (especially for big strings), String.prototype.replace allows the browser to automatically handle the underlying memory management of resizing the string, causing a significant performance boost especially in evergreen browsers like Chrome and Firefox that heavily optimize String.prototype.replace. Finally, the icing on the cake is that for you latin script exclūsīvō users, strings which don't contain any code points above 0x7f are extra super fast to process because the string remains unmodified by the replacement algorithm.

(see also https://stackoverflow.com/a/53433503/5601591)
(see also The MDN Page Base64_encoding_and_decoding)

Example Usage

The below code snippet was taken from the demonstration page. This demonstration page can be viewed live here via Github Pages.

(function(window, btoaUTF8){
    "use strict";
    var sourceEle = document.getElementById("source");
    var urlBarEle = document.getElementById("urlBar");
    var mainFrameEle = document.getElementById("mainframe");
    var gotoButton = document.getElementById("gotoButton");
    var parseInt = window.parseInt;
    var fromCodePoint = String.fromCodePoint;
    var parse = JSON.parse;
    
    function unescape(str){
        return str.replace(/\\u[\da-f]{0,4}|\\x[\da-f]{0,2}|\\u{[^}]*}|\\[bfnrtv"'\\]|\\0[0-7]{1,3}|\\\d{1,3}/g, function(match){
          try{
            if (match.startsWith("\\u{"))
              return fromCodePoint(parseInt(match.slice(2,-1),16));
            if (match.startsWith("\\u") || match.startsWith("\\x"))
              return fromCodePoint(parseInt(match.substring(2),16));
            if (match.startsWith("\\0") && match.length > 2)
              return fromCodePoint(parseInt(match.substring(2),8));
            if (/^\\\d/.test(match)) return fromCodePoint(+match.slice(1));
          }catch(e){
	  	for (var str="", i=match.length; i--; ) str += match.charAt(i);
		return str;
	  }
          return parse('"' + match + '"');
        });
    }
    
    function whenChange(){
      try{ urlBarEle.value = "data:text/plain;base64," + btoaUTF8(unescape(sourceEle.value), true);
      } finally{ gotoURL(); }
    }
    sourceEle.addEventListener("change",whenChange,{passive:1});
    sourceEle.addEventListener("input",whenChange,{passive:1});
    
    // IFrame Setup:
    function gotoURL(){mainFrameEle.src = urlBarEle.value}
    gotoButton.addEventListener("click", gotoURL, {passive: 1});
    function urlChanged(){urlBarEle.value = mainFrameEle.src}
    mainFrameEle.addEventListener("load", urlChanged, {passive: 1});
    urlBarEle.addEventListener("keypress", function(evt){
      if (evt.key === "enter") evt.preventDefault(), urlChanged();
    }, {passive: 1});
    setTimeout(whenChange, 0);
})(window, btoaUTF8);

SpiderNode (Hooray!) / NodeJS (Booo!)

Simply drop the file atobAndBtoaTogether.node.js into the same folder as your Javascript node file. Then, add the following to the Javascript in the SpiderNode/NodeJS file.

var AtobAndBtoaTogether = require("./atobAndBtoaTogether.node.js");

Then, here is the node API:

• /*String*/ AtobAndBtoaTogether.btoaUTF8(/*String*/ originalString, /*boolean*/ autoBOMit = false)

  • Encodes the binary string originalString into valid base 64.
  • autoBOMit determines whether to append a BOM on to the end of the string. Only use this when the base64 is to be used as a data URI link. If you have no idea what this means and are confused, then simply ignore this option and it should not give you any problems.

• /*String*/ AtobAndBtoaTogether.atobUTF8(/*String*/ encodedBase64String, /*boolean*/ keepBOM = false)

  • Decodes the base64 string encodedBase64String into its original UTF8 binary counterpart.
  • keepBOM will keep the BOM of the string. Use this option if you are certain that the original UTF8 string was raw binary data. Keep this option false if you used the autoBOMit option when encoding the string.

Enjoy!