i18n.js

/**
 * @license RequireJS i18n 2.0.1 Copyright (c) 2010-2012, The Dojo Foundation All Rights Reserved.
 * Available via the MIT or new BSD license.
 * see: http://github.com/requirejs/i18n for details
 */
/*jslint regexp: true */
/*global require: false, navigator: false, define: false */

/**
 * This plugin handles i18n! prefixed modules. It does the following:
 *
 * 1) A regular module can have a dependency on an i18n bundle, but the regular
 * module does not want to specify what locale to load. So it just specifies
 * the top-level bundle, like "i18n!nls/colors".
 *
 * This plugin will load the i18n bundle at nls/colors, see that it is a root/master
 * bundle since it does not have a locale in its name. It will then try to find
 * the best match locale available in that master bundle, then request all the
 * locale pieces for that best match locale. For instance, if the locale is "en-us",
 * then the plugin will ask for the "en-us", "en" and "root" bundles to be loaded
 * (but only if they are specified on the master bundle).
 *
 * Once all the bundles for the locale pieces load, then it mixes in all those
 * locale pieces into each other, then finally sets the context.defined value
 * for the nls/colors bundle to be that mixed in locale.
 *
 * 2) A regular module specifies a specific locale to load. For instance,
 * i18n!nls/fr-fr/colors. In this case, the plugin needs to load the master bundle
 * first, at nls/colors, then figure out what the best match locale is for fr-fr,
 * since maybe only fr or just root is defined for that locale. Once that best
 * fit is found, all of its locale pieces need to have their bundles loaded.
 *
 * Once all the bundles for the locale pieces load, then it mixes in all those
 * locale pieces into each other, then finally sets the context.defined value
 * for the nls/fr-fr/colors bundle to be that mixed in locale.
 */
(function () {
    'use strict';

    //regexp for reconstructing the master bundle name from parts of the regexp match
    //nlsRegExp.exec("foo/bar/baz/nls/en-ca/foo") gives:
    //["foo/bar/baz/nls/en-ca/foo", "foo/bar/baz/nls/", "/", "/", "en-ca", "foo"]
    //nlsRegExp.exec("foo/bar/baz/nls/foo") gives:
    //["foo/bar/baz/nls/foo", "foo/bar/baz/nls/", "/", "/", "foo", ""]
    //so, if match[5] is blank, it means this is the top bundle definition.
    var nlsRegExp = /(^.*(^|\/)nls(\/|$))([^\/]*)\/?([^\/]*)/;

    //Helper function to avoid repeating code. Lots of arguments in the
    //desire to stay functional and support RequireJS contexts without having
    //to know about the RequireJS contexts.
    function addPart(locale, master, needed, toLoad, prefix, suffix) {
        if (master[locale]) {
            needed.push(locale);
            if (master[locale] === true || master[locale] === 1) {
                toLoad.push(prefix + locale + '/' + suffix);
            }
        }
    }

    function addIfExists(req, locale, toLoad, prefix, suffix) {
        var fullName = prefix + locale + '/' + suffix;
        if (require._fileExists(req.toUrl(fullName))) {
            toLoad.push(fullName);
        }
    }

    /**
     * Simple function to mix in properties from source into target,
     * but only if target does not already have a property of the same name.
     * This is not robust in IE for transferring methods that match
     * Object.prototype names, but the uses of mixin here seem unlikely to
     * trigger a problem related to that.
     */
    function mixin(target, source, force) {
        var prop;
        for (prop in source) {
            if (source.hasOwnProperty(prop) && (!target.hasOwnProperty(prop) || force)) {
                target[prop] = source[prop];
            } else if (typeof source[prop] === 'object') {
                mixin(target[prop], source[prop], force);
            }
        }
    }

    define(['module'], function (module) {
        var masterConfig = module.config();

        return {
            version: '2.0.1',
            /**
             * Called when a dependency needs to be loaded.
             */
            load: function (name, req, onLoad, config) {
                config = config || {};

                if (config.locale) {
                    masterConfig.locale = config.locale;
                }

                var masterName,
                    match = nlsRegExp.exec(name),
                    prefix = match[1],
                    locale = match[4],
                    suffix = match[5],
                    parts = locale.split("-"),
                    toLoad = [],
                    value = {},
                    i, part, current = "";

                //If match[5] is blank, it means this is the top bundle definition,
                //so it does not have to be handled. Locale-specific requests
                //will have a match[4] value but no match[5]
                if (match[5]) {
                    //locale-specific bundle
                    prefix = match[1];
                    masterName = prefix + suffix;
                } else {
                    //Top-level bundle.
                    masterName = name;
                    suffix = match[4];
                    locale = masterConfig.locale;
                    if (!locale) {
                        locale = masterConfig.locale =
                            typeof navigator === "undefined" ? "root" :
                            (navigator.language ||
                             navigator.userLanguage || "root").toLowerCase();
                    }
                    parts = locale.split("-");
                }

                if (config.isBuild) {
                    //Check for existence of all locale possible files and
                    //require them if exist.
                    toLoad.push(masterName);
                    addIfExists(req, "root", toLoad, prefix, suffix);
                    for (i = 0; i < parts.length; i++) {
                        part = parts[i];
                        current += (current ? "-" : "") + part;
                        addIfExists(req, current, toLoad, prefix, suffix);
                    }

                    req(toLoad, function () {
                        onLoad();
                    });
                } else {
                    //First, fetch the master bundle, it knows what locales are available.
                    req([masterName], function (master) {
                        //Figure out the best fit
                        var needed = [],
                            part;

                        //Always allow for root, then do the rest of the locale parts.
                        addPart("root", master, needed, toLoad, prefix, suffix);
                        for (i = 0; i < parts.length; i++) {
                            part = parts[i];
                            current += (current ? "-" : "") + part;
                            addPart(current, master, needed, toLoad, prefix, suffix);
                        }

                        //Load all the parts missing.
                        req(toLoad, function () {
                            var i, partBundle, part;
                            for (i = needed.length - 1; i > -1 && needed[i]; i--) {
                                part = needed[i];
                                partBundle = master[part];
                                if (partBundle === true || partBundle === 1) {
                                    partBundle = req(prefix + part + '/' + suffix);
                                }
                                mixin(value, partBundle);
                            }

                            //All done, notify the loader.
                            onLoad(value);
                        });
                    });
                }
            }
        };
    });
}());