quoted-printable is a character encoding–agnostic JavaScript implementation of the Quoted-Printable content transfer encoding as defined by RFC 2045. It can be used to encode plaintext to its Quoted-Printable encoding, or the other way around (i.e. decoding). Here’s an online demo using the UTF-8 character encoding.

Via npm:

npm install quoted-printable

Via Bower:

bower install quoted-printable

Via Component:

component install mathiasbynens/quoted-printable

In a browser:

<script src="quoted-printable.js"></script>

In Node.js, io.js, Narwhal, and RingoJS:

var quotedPrintable = require('quoted-printable');

In Rhino:

load('quoted-printable.js');

Using an AMD loader like RequireJS:

require(
  {
    'paths': {
      'quoted-printable': 'path/to/quoted-printable'
    }
  },
  ['quoted-printable'],
  function(quotedPrintable) {
    console.log(quotedPrintable);
  }
);

A string representing the semantic version number.

This function takes an encoded byte string (the input parameter) and Quoted-Printable-encodes it. Each item in the input string represents an octet as per the desired character encoding. Here’s an example that uses UTF-8:

var utf8 = require('utf8');

quotedPrintable.encode(utf8.encode('foo=bar'));
// → 'foo=3Dbar'

quotedPrintable.encode(utf8.encode('Iñtërnâtiônàlizætiøn☃💩'));
// → 'I=C3=B1t=C3=ABrn=C3=A2ti=C3=B4n=C3=A0liz=C3=A6ti=C3=B8n=E2=98=83=F0=9F=92=\r\n=A9'

This function takes a string of text (the text parameter) and Quoted-Printable-decodes it. The return value is a ‘byte string’, i.e. a string of which each item represents an octet as per the character encoding that’s being used. Here’s an example that uses UTF-8:

var utf8 = require('utf8');

utf8.decode(quotedPrintable.decode('foo=3Dbar'));
// → 'foo=bar'

utf8.decode(quotedPrintable.decode('I=C3=B1t=C3=ABrn=C3=A2ti=C3=B4n=C3=A0liz=C3=A6ti=C3=B8n=E2=98=83=F0=9F=92=\r\n=A9'));
// → 'Iñtërnâtiônàlizætiøn☃💩'

To use the quoted-printable binary in your shell, simply install quoted-printable globally using npm:

npm install -g quoted-printable

After that, you’ll be able to use quoted-printable on the command line. Note that while the quoted-printable library itself is character encoding–agnostic, the command-line tool applies the UTF-8 character encoding on all input.

$ quoted-printable --encode 'foo=bar'
foo=3Dbar

$ quoted-printable --decode 'foo=3Dbar'
foo=bar

Read a local text file, Quoted-Printable-encode it, and save the result to a new file:

$ quoted-printable --encode < foo.txt > foo-quoted-printable.txt

Or do the same with an online text file:

$ curl -sL 'https://mths.be/brh' | quoted-printable --encode > quoted-printable.txt

Or, the opposite — read a local file containing a Quoted-Printable-encoded message, decode it back to plain text, and save the result to a new file:

$ quoted-printable --decode < quoted-printable.txt > original.txt

See quoted-printable --help for the full list of options.

quoted-printable is designed to work in at least Node.js v0.10.0, io.js v1.0.0, Narwhal 0.3.2, RingoJS 0.8-0.11, PhantomJS 1.9.0, Rhino 1.7RC4, as well as old and modern versions of Chrome, Firefox, Safari, Opera, and Internet Explorer.

After cloning this repository, run npm install to install the dependencies needed for development and testing. You may want to install Istanbul globally using npm install istanbul -g.

Once that’s done, you can run the unit tests in Node using npm test or node tests/tests.js. To run the tests in Rhino, Ringo, Narwhal, and web browsers as well, use grunt test.

To generate the code coverage report, use grunt cover.

Mathias Bynens

quoted-printable is available under the MIT license.