Simple lightweight polyfill for the Text Encoding API, supporting UTF-8 only

encoding, decoding, w3c, utf-8, polyfill, shim, textdecoder, textencoder
npm install text-encoding-shim@1.0.5


Text Encoding Shim

When I was looking for a simple lightweight polyfill that works great with TypeScript I was not happy with the results. While a couple polyfills exist, they either broke in my special setup and lead to unexpected results or they implemented a bunch of features that I did not even want to have. So I wrote my own shim.



Get it via npm by adding text-encoding-shim to your package.json or run:

npm install text-encoding-shim


Get it via Bower by adding it to your bower.json or run:

bower install --save text-encoding-shim

HTML script tag

Altenatively you can simply download this project folder from Gitlab and add it to your html script tags like so:

<script type="text/javascript" src="text-encoding-shim/index.js"></script>

TypeScript definitions

If you are using TypeScript you do not need to create a definition file. This project already includes one. If you are still using typings you may need to run this command to copy the file:

typings install --save --global npm:text-encoding-shim

Importing the polyfill

This polyfill utilizes the Universal Module Definition (UMD) and be used with either a module loader or standalone. If you import it by adding a script tag you do not have to do anything else. It will automatically be bound to the global scope.


var TextEncodingShim = require('text-encoding-shim');
var TextEncoder = TextEncodingShim.TextEncoder;
var TextDecoder = TextEncodingShim.TextDecoder;

Asynchronous Module Definition (AMD)

define([TextEncodingShim], function() {

ES2015 or TypeScript

import { TextEncoder, TextDecoder } from 'text-encoding-shim';

Basic Usage

var uint8array = new TextEncoder('utf-8').encode(string);
var string = new TextDecoder('utf-8').decode(uint8array);


If a native implementation is available it will always be handled preferred to this polyfill. Just like native implementations of Mozilla Firefox or Google Chrome, this library only supports UTF-8 encoding. This makes it so fast. If you need additional encodings, check out this more advanced polyfill.