swapcase is a letter case swapper with full Unicode support, i.e. based on the official Unicode case folding mappings.

Via npm:

npm install swapcase

Via Bower:

bower install swapcase

Via Component:

component install mathiasbynens/swapcase

In a browser:

<script src="swapcase.js"></script>

In Narwhal, Node.js, and RingoJS:

var swapCase = require('swapcase');

In Rhino:

load('swapcase.js');

Using an AMD loader like RequireJS:

require(
  {
    'paths': {
      'swapcase': 'path/to/swapcase'
    }
  },
  ['swapcase'],
  function(swapCase) {
    console.log(swapCase);
  }
);

A string representing the semantic version number.

This function takes a string of text and swaps the case for each letter: lowercase letters become uppercase letters, and vice versa. All the Unicode ‘Full’ case folding mappings are used.

swapcase.encode('aBcDeFg');
// → 'AbCdEfG'

To use the swapcase binary in your shell, simply install swapcase globally using npm:

npm install -g swapcase

After that you will be able to case-swap text from the command line:

$ swapcase 'föo ♥ bår 𝌆 baz'
FÖO ♥ BÅR 𝌆 BAZ

Read a local text file, case-swap any letters it contains, and save the result to a new file:

$ swapcase < foo.txt > foo-case-swapped.html

Or do the same with an online text file:

$ curl -sL "https://git.io/HnfEaw" | swapcase > case-swapped.html

See swapcase --help for the full list of options.

swapcase has been tested in at least Chrome 27-29, Firefox 3-22, Safari 4-6, Opera 10-12, IE 6-10, Node.js v0.10.0, Narwhal 0.3.2, RingoJS 0.8-0.9, PhantomJS 1.9.0, and Rhino 1.7RC4.

After cloning this repository, run npm install to install the dependencies needed for swapcase 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

swapcase is available under the MIT license.