This Javascript library provides the most performant tiny polyfill for window.TextEncoder and window.TextDecoder for use in the browser, in NodeJS, in RequireJS, in web Workers, in SharedWorkers, and in ServiceWorkers.

Add the following HTML Code to your head:

<script src="https://dl.dropboxusercontent.com/s/r55397ld512etib/EncoderDecoderTogether.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 less blocking version below:

<script defer="" src="https://dl.dropboxusercontent.com/s/r55397ld512etib/EncoderDecoderTogether.min.js?dl=0" type="text/javascript"></script>

Alternatively, either use https://dl.dropboxusercontent.com/s/47481btie8pb95h/FastestTextEncoderPolyfill.min.js?dl=0 to polyfill window.TextEncoder for converting a String into a Uint8Array or use https://dl.dropboxusercontent.com/s/qmoknmp86sytc74/FastestTextDecoderPolyfill.min.js?dl=0 to only polyfill window.TextDecoder for converting a Uint8Array/ArrayBuffer/[typedarray]/global.Buffer into a String.

For dropping into either RequireJS or NodeJS, please use the fastestsmallesttextencoderdecoder npm repository, this minified file, or the corresponding source code file.

This polyfill will bring support for TextEncoder/TextDecoder to the following browsers.

Feature	Chrome	Firefox	Opera	Edge	Internet Explorer	Safari	Android	Samsung Internet	Node.js
Full Polyfill	7.0	4.0	11.6	12.0**	10	5.1 (Desktop) / 4.2 (iOS)	4.0	1.0	3.0
Partial Polyfill*	1.0	0.6	7.0 (Desktop) / 9.5** (Mobile)	12.0**	4.0	2.0	1.0	1.0	0.10

Also note that while this polyfill may work in these old browsers, it is very likely that the rest of your website will not (unless if you make a concious effort about it which I would not reccomend because noone uses or should use these old browsers).

* Partial polyfill means that Array (or ArrayBuffer in NodeJS) will be used instead of Uint8Array/[typedarray].

** This is the first public release of the browser

Please review the MDN at window.TextEncoder and window.TextDecoder for information on how to use TextEncoder and TextDecoder.

As for NodeJS, calling require("EncoderAndDecoderNodeJS.min.js") yields the following object:

module.exports = {
	TextEncoder: function TextEncoder(){/*...*/},
	TextDecoder: function TextEncoder(){/*...*/},
	encode: TextEncoder.prototype.encode,
	decode: TextDecoder.prototype.decode
}

Thus, in NodeJS, you do not ever have to use new just to get the encoder/decoder (although you still can do so if you want to). All of the code snippets below function identically _{(aside from unused local variables introduced into the scope)}. There are an innumerable number of ways to rewrite this same snippet of code, thus I only chose the three which I thought would be most useful.

    // Variation 1
    const {TextEncoder, TextDecoder} = require("EncoderAndDecoderNodeJS.min.js");
    const encode = (new TextEncoder).encode;
    const decode = (new TextDecoder).decode;

    // Variation 2
    const {encode, decode} = require("EncoderAndDecoderNodeJS.min.js");

    // Variation 3
    const encodeAndDecodeModule = require("EncoderAndDecoderNodeJS.min.js");
    const encode = encodeAndDecodeModule.encode;
    const decode = encodeAndDecodeModule.decode;

Visit the GithubPage to see a demonstation. As seen in the Web Worker hexWorker.js, the Github Pages demonstration uses a special encoderAndDecoderForced.src.js version of this library to forcefully install the TextEncoder and TextDecoder even when there is native support. That way, this demonstraton should serve to truthfully demonstrate this polyfill.

You can find this project on npm here at this link.