messageformat.js

The experience and subtlety of your program's text can be important. MessageFormat is a mechanism for handling both pluralization and gender in your applications. It can also lead to much better translations, as it's designed to support all the languages included in the Unicode CLDR.

The ICU has an official guide for the format. Messageformat.js supports and extends all parts of the standard, with the exception of the deprecated ChoiceFormat.

There is a good slide-deck on Plural and Gender in Translated Messages by Markus Scherer and Mark Davis. But, again, remember that many of these problems apply even if you're only outputting english.

Please see messageformat.github.io for a guide to MessageFormat, more information on on the build-time use of messageformat.js, and the code documentation.

What problems does it solve?

Using messageformat.js, you can separate your code from your text formatting, while enabling much more humane expressions. In other words, you won't need to see this anymore in your output:

There are 1 results.
There are 1 result(s).
Number of results: 5.

What does it look like?

With this message:

> var msg =
  '{GENDER, select, male{He} female{She} other{They} }' +
  ' found ' +
  '{RES, plural, =0{no results} one{1 result} other{# results} }' +
  ' in the ' +
  '{CAT, selectordinal, one{#st} two{#nd} few{#rd} other{#th} }' +
  ' category.';

You'll get these results:

> var mfunc = new MessageFormat('en').compile(msg);

> mfunc({ GENDER: 'male', RES: 1, CAT: 2 })
'He found 1 result in the 2nd category.'

> mfunc({ GENDER: 'female', RES: 1, CAT: 2 })
'She found 1 result in the 2nd category.'

> mfunc({ GENDER: 'male', RES: 2, CAT: 1 })
'He found 2 results in the 1st category.'

> mfunc({ RES: 2, CAT: 2 })
'They found 2 results in the 2nd category.'

Features

Handles arbitrary nesting of pluralization and select rules
Supports all ~466 languages included in the Unicode CLDR
Works on the server and the client
Remarkably useful even for single-language use
Speed & efficiency: Can pre-compile messages to JavaScript code
- Great for speed: message formatting is just string concatenation
Compatible with other MessageFormat implementations
Extendable with custom formatting functions
Very whitespace tolerant
Supports Unicode

Installation

Node

npm install messageformat

var MessageFormat = require('messageformat');
var mf = new MessageFormat('en');

Bower

bower install messageformat

<script src="path/to/bower_components/messageformat/messageformat.js"></script>
<script>
  var mf = new MessageFormat('en');
</script>

License

You may use this software under the MIT License.

You may contribute to this software under the Dojo CLA.

Authors

Alex Sexton - @SlexAxton - http://alexsexton.com/
Eemeli Aro - @eemeli - https://github.com/eemeli

Credits

Thanks to:

Bazaarvoice - my previous employer - for letting me do cool stuff like this.
Google has an implementation that is similar in Google Closure, I tried to vet my code against many of their tests.
Norbert Lindenberg for showing me how good it can be.

Implementations in other languages

Jeff Hansen (@jeffijoe) has written an implementation for .NET - it's a Portable Class Library, making it possible to use on iOS, Android, Windows Phone, and pretty much any other .NET target.

Additional tools

icu-converter is a NodeJS tool for converting message files in the ICU Resource Bundle format into JSON or .property files.

OliverFischer/messageformat.js