i18n.js

// I18n.js
// =======
//
// This small library provides the Rails I18n API on the Javascript.
// You don't actually have to use Rails (or even Ruby) to use I18n.js.
// Just make sure you export all translations in an object like this:
//
//     I18n.translations.en = {
//       hello: "Hello World"
//     };
//
// See tests for specific formatting like numbers and dates.
//

;(function(factory) {
  if (typeof module !== 'undefined' && module.exports) {
    // Node/CommonJS
    module.exports = factory(this);
  } else if (typeof define === 'function' && define.amd) {
    // AMD
    var global=this;
    define('i18n', function(){ return factory(global);});
  } else {
    // Browser globals
    this.I18n = factory(this);
  }
}(function(global) {
  "use strict";

  // Use previously defined object if exists in current scope
  var I18n = global && global.I18n || {};

  // Just cache the Array#slice function.
  var slice = Array.prototype.slice;

  // Apply number padding.
  var padding = function(number) {
    return ("0" + number.toString()).substr(-2);
  };

  // Improved toFixed number rounding function with support for unprecise floating points
  // JavaScript's standard toFixed function does not round certain numbers correctly (for example 0.105 with precision 2).
  var toFixed = function(number, precision) {
    return decimalAdjust('round', number, -precision).toFixed(precision);
  };

  // Is a given variable an object?
  // Borrowed from Underscore.js
  var isObject = function(obj) {
    var type = typeof obj;
    return type === 'function' || type === 'object' && !!obj;
  };

  // Is a given value an array?
  // Borrowed from Underscore.js
  var isArray = function(obj) {
    if (Array.isArray) {
      return Array.isArray(obj);
    };
    return Object.prototype.toString.call(obj) === '[object Array]';
  };

  var decimalAdjust = function(type, value, exp) {
    // If the exp is undefined or zero...
    if (typeof exp === 'undefined' || +exp === 0) {
      return Math[type](value);
    }
    value = +value;
    exp = +exp;
    // If the value is not a number or the exp is not an integer...
    if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0)) {
      return NaN;
    }
    // Shift
    value = value.toString().split('e');
    value = Math[type](+(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp)));
    // Shift back
    value = value.toString().split('e');
    return +(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp));
  }

  // Set default days/months translations.
  var DATE = {
      day_names: ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"]
    , abbr_day_names: ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]
    , month_names: [null, "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]
    , abbr_month_names: [null, "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
    , meridian: ["AM", "PM"]
  };

  // Set default number format.
  var NUMBER_FORMAT = {
      precision: 3
    , separator: "."
    , delimiter: ","
    , strip_insignificant_zeros: false
  };

  // Set default currency format.
  var CURRENCY_FORMAT = {
      unit: "$"
    , precision: 2
    , format: "%u%n"
    , sign_first: true
    , delimiter: ","
    , separator: "."
  };

  // Set default percentage format.
  var PERCENTAGE_FORMAT = {
      unit: "%"
    , precision: 3
    , format: "%n%u"
    , separator: "."
    , delimiter: ""
  };

  // Set default size units.
  var SIZE_UNITS = [null, "kb", "mb", "gb", "tb"];

  // Other default options
  var DEFAULT_OPTIONS = {
    // Set default locale. This locale will be used when fallback is enabled and
    // the translation doesn't exist in a particular locale.
      defaultLocale: "en"
    // Set the current locale to `en`.
    , locale: "en"
    // Set the translation key separator.
    , defaultSeparator: "."
    // Set the placeholder format. Accepts `{{placeholder}}` and `%{placeholder}`.
    , placeholder: /(?:\{\{|%\{)(.*?)(?:\}\}?)/gm
    // Set if engine should fallback to the default locale when a translation
    // is missing.
    , fallbacks: false
    // Set the default translation object.
    , translations: {}
    // Set missing translation behavior. 'message' will display a message
    // that the translation is missing, 'guess' will try to guess the string
    , missingBehaviour: 'message'
    // if you use missingBehaviour with 'message', but want to know that the
    // string is actually missing for testing purposes, you can prefix the
    // guessed string by setting the value here. By default, no prefix!
    , missingTranslationPrefix: ''
  };

  I18n.reset = function() {
    // Set default locale. This locale will be used when fallback is enabled and
    // the translation doesn't exist in a particular locale.
    this.defaultLocale = DEFAULT_OPTIONS.defaultLocale;

    // Set the current locale to `en`.
    this.locale = DEFAULT_OPTIONS.locale;

    // Set the translation key separator.
    this.defaultSeparator = DEFAULT_OPTIONS.defaultSeparator;

    // Set the placeholder format. Accepts `{{placeholder}}` and `%{placeholder}`.
    this.placeholder = DEFAULT_OPTIONS.placeholder;

    // Set if engine should fallback to the default locale when a translation
    // is missing.
    this.fallbacks = DEFAULT_OPTIONS.fallbacks;

    // Set the default translation object.
    this.translations = DEFAULT_OPTIONS.translations;

    // Set the default missing behaviour
    this.missingBehaviour = DEFAULT_OPTIONS.missingBehaviour;

    // Set the default missing string prefix for guess behaviour
    this.missingTranslationPrefix = DEFAULT_OPTIONS.missingTranslationPrefix;

  };

  // Much like `reset`, but only assign options if not already assigned
  I18n.initializeOptions = function() {
    if (typeof(this.defaultLocale) === "undefined" && this.defaultLocale !== null)
      this.defaultLocale = DEFAULT_OPTIONS.defaultLocale;

    if (typeof(this.locale) === "undefined" && this.locale !== null)
      this.locale = DEFAULT_OPTIONS.locale;

    if (typeof(this.defaultSeparator) === "undefined" && this.defaultSeparator !== null)
      this.defaultSeparator = DEFAULT_OPTIONS.defaultSeparator;

    if (typeof(this.placeholder) === "undefined" && this.placeholder !== null)
      this.placeholder = DEFAULT_OPTIONS.placeholder;

    if (typeof(this.fallbacks) === "undefined" && this.fallbacks !== null)
      this.fallbacks = DEFAULT_OPTIONS.fallbacks;

    if (typeof(this.translations) === "undefined" && this.translations !== null)
      this.translations = DEFAULT_OPTIONS.translations;
  };
  I18n.initializeOptions();

  // Return a list of all locales that must be tried before returning the
  // missing translation message. By default, this will consider the inline option,
  // current locale and fallback locale.
  //
  //     I18n.locales.get("de-DE");
  //     // ["de-DE", "de", "en"]
  //
  // You can define custom rules for any locale. Just make sure you return a array
  // containing all locales.
  //
  //     // Default the Wookie locale to English.
  //     I18n.locales["wk"] = function(locale) {
  //       return ["en"];
  //     };
  //
  I18n.locales = {};

  // Retrieve locales based on inline locale, current locale or default to
  // I18n's detection.
  I18n.locales.get = function(locale) {
    var result = this[locale] || this[I18n.locale] || this["default"];

    if (typeof(result) === "function") {
      result = result(locale);
    }

    if (isArray(result) === false) {
      result = [result];
    }

    return result;
  };

  // The default locale list.
  I18n.locales["default"] = function(locale) {
    var locales = []
      , list = []
      , countryCode
      , count
    ;

    // Handle the inline locale option that can be provided to
    // the `I18n.t` options.
    if (locale) {
      locales.push(locale);
    }

    // Add the current locale to the list.
    if (!locale && I18n.locale) {
      locales.push(I18n.locale);
    }

    // Add the default locale if fallback strategy is enabled.
    if (I18n.fallbacks && I18n.defaultLocale) {
      locales.push(I18n.defaultLocale);
    }

    // Compute each locale with its country code.
    // So this will return an array containing both
    // `de-DE` and `de` locales.
    locales.forEach(function(locale){
      countryCode = locale.split("-")[0];

      if (!~list.indexOf(locale)) {
        list.push(locale);
      }

      if (I18n.fallbacks && countryCode && countryCode !== locale && !~list.indexOf(countryCode)) {
        list.push(countryCode);
      }
    });

    // No locales set? English it is.
    if (!locales.length) {
      locales.push("en");
    }

    return list;
  };

  // Hold pluralization rules.
  I18n.pluralization = {};

  // Return the pluralizer for a specific locale.
  // If no specify locale is found, then I18n's default will be used.
  I18n.pluralization.get = function(locale) {
    return this[locale] || this[I18n.locale] || this["default"];
  };

  // The default pluralizer rule.
  // It detects the `zero`, `one`, and `other` scopes.
  I18n.pluralization["default"] = function(count) {
    switch (count) {
      case 0: return ["zero", "other"];
      case 1: return ["one"];
      default: return ["other"];
    }
  };

  // Return current locale. If no locale has been set, then
  // the current locale will be the default locale.
  I18n.currentLocale = function() {
    return this.locale || this.defaultLocale;
  };

  // Check if value is different than undefined and null;
  I18n.isSet = function(value) {
    return value !== undefined && value !== null;
  };

  // Find and process the translation using the provided scope and options.
  // This is used internally by some functions and should not be used as an
  // public API.
  I18n.lookup = function(scope, options) {
    options = this.prepareOptions(options);

    var locales = this.locales.get(options.locale).slice()
      , requestedLocale = locales[0]
      , locale
      , scopes
      , translations
    ;

    scope = this.getFullScope(scope, options);

    while (locales.length) {
      locale = locales.shift();
      scopes = scope.split(this.defaultSeparator);
      translations = this.translations[locale];

      if (!translations) {
        continue;
      }

      while (scopes.length) {
        translations = translations[scopes.shift()];

        if (translations === undefined || translations === null) {
          break;
        }
      }

      if (translations !== undefined && translations !== null) {
        return translations;
      }
    }

    if (this.isSet(options.defaultValue)) {
      return options.defaultValue;
    }
  };

  // Rails changed the way the meridian is stored.
  // It started with `date.meridian` returning an array,
  // then it switched to `time.am` and `time.pm`.
  // This function abstracts this difference and returns
  // the correct meridian or the default value when none is provided.
  I18n.meridian = function() {
    var time = this.lookup("time");
    var date = this.lookup("date");

    if (time && time.am && time.pm) {
      return [time.am, time.pm];
    } else if (date && date.meridian) {
      return date.meridian;
    } else {
      return DATE.meridian;
    }
  };

  // Merge serveral hash options, checking if value is set before
  // overwriting any value. The precedence is from left to right.
  //
  //     I18n.prepareOptions({name: "John Doe"}, {name: "Mary Doe", role: "user"});
  //     #=> {name: "John Doe", role: "user"}
  //
  I18n.prepareOptions = function() {
    var args = slice.call(arguments)
      , options = {}
      , subject
    ;

    while (args.length) {
      subject = args.shift();

      if (typeof(subject) != "object") {
        continue;
      }

      for (var attr in subject) {
        if (!subject.hasOwnProperty(attr)) {
          continue;
        }

        if (this.isSet(options[attr])) {
          continue;
        }

        options[attr] = subject[attr];
      }
    }

    return options;
  };

  // Generate a list of translation options for default fallbacks.
  // `defaultValue` is also deleted from options as it is returned as part of
  // the translationOptions array.
  I18n.createTranslationOptions = function(scope, options) {
    var translationOptions = [{scope: scope}];

    // Defaults should be an array of hashes containing either
    // fallback scopes or messages
    if (this.isSet(options.defaults)) {
      translationOptions = translationOptions.concat(options.defaults);
    }

    // Maintain support for defaultValue. Since it is always a message
    // insert it in to the translation options as such.
    if (this.isSet(options.defaultValue)) {
      translationOptions.push({ message: options.defaultValue });
      delete options.defaultValue;
    }

    return translationOptions;
  };

  // Translate the given scope with the provided options.
  I18n.translate = function(scope, options) {
    options = this.prepareOptions(options);

    var translationOptions = this.createTranslationOptions(scope, options);

    var translation;
    // Iterate through the translation options until a translation
    // or message is found.
    var translationFound =
      translationOptions.some(function(translationOption) {
        if (this.isSet(translationOption.scope)) {
          translation = this.lookup(translationOption.scope, options);
        } else if (this.isSet(translationOption.message)) {
          translation = translationOption.message;
        }

        if (translation !== undefined && translation !== null) {
          return true;
        }
      }, this);

    if (!translationFound) {
      return this.missingTranslation(scope, options);
    }

    if (typeof(translation) === "string") {
      translation = this.interpolate(translation, options);
    } else if (isObject(translation) && this.isSet(options.count)) {
      translation = this.pluralize(options.count, translation, options);
    }

    return translation;
  };

  // This function interpolates the all variables in the given message.
  I18n.interpolate = function(message, options) {
    options = this.prepareOptions(options);
    var matches = message.match(this.placeholder)
      , placeholder
      , value
      , name
      , regex
    ;

    if (!matches) {
      return message;
    }

    var value;

    while (matches.length) {
      placeholder = matches.shift();
      name = placeholder.replace(this.placeholder, "$1");

      if (this.isSet(options[name])) {
        value = options[name].toString().replace(/\$/gm, "_#$#_");
      } else if (name in options) {
        value = this.nullPlaceholder(placeholder, message, options);
      } else {
        value = this.missingPlaceholder(placeholder, message, options);
      }

      regex = new RegExp(placeholder.replace(/\{/gm, "\\{").replace(/\}/gm, "\\}"));
      message = message.replace(regex, value);
    }

    return message.replace(/_#\$#_/g, "$");
  };

  // Pluralize the given scope using the `count` value.
  // The pluralized translation may have other placeholders,
  // which will be retrieved from `options`.
  I18n.pluralize = function(count, scope, options) {
    options = this.prepareOptions(options);
    var translations, pluralizer, keys, key, message;

    if (isObject(scope)) {
      translations = scope;
    } else {
      translations = this.lookup(scope, options);
    }

    if (!translations) {
      return this.missingTranslation(scope, options);
    }

    pluralizer = this.pluralization.get(options.locale);
    keys = pluralizer(count);

    while (keys.length) {
      key = keys.shift();

      if (this.isSet(translations[key])) {
        message = translations[key];
        break;
      }
    }

    options.count = String(count);
    return this.interpolate(message, options);
  };

  // Return a missing translation message for the given parameters.
  I18n.missingTranslation = function(scope, options) {
    //guess intended string
    if(this.missingBehaviour == 'guess'){
      //get only the last portion of the scope
      var s = scope.split('.').slice(-1)[0];
      //replace underscore with space && camelcase with space and lowercase letter
      return (this.missingTranslationPrefix.length > 0 ? this.missingTranslationPrefix : '') +
          s.replace('_',' ').replace(/([a-z])([A-Z])/g,
          function(match, p1, p2) {return p1 + ' ' + p2.toLowerCase()} );
    }

    var fullScope           = this.getFullScope(scope, options);
    var fullScopeWithLocale = [this.currentLocale(), fullScope].join(this.defaultSeparator);

    return '[missing "' + fullScopeWithLocale + '" translation]';
  };

  // Return a missing placeholder message for given parameters
  I18n.missingPlaceholder = function(placeholder, message, options) {
    return "[missing " + placeholder + " value]";
  };

  I18n.nullPlaceholder = function() {
    return I18n.missingPlaceholder.apply(I18n, arguments);
  };

  // Format number using localization rules.
  // The options will be retrieved from the `number.format` scope.
  // If this isn't present, then the following options will be used:
  //
  // - `precision`: `3`
  // - `separator`: `"."`
  // - `delimiter`: `","`
  // - `strip_insignificant_zeros`: `false`
  //
  // You can also override these options by providing the `options` argument.
  //
  I18n.toNumber = function(number, options) {
    options = this.prepareOptions(
        options
      , this.lookup("number.format")
      , NUMBER_FORMAT
    );

    var negative = number < 0
      , string = toFixed(Math.abs(number), options.precision).toString()
      , parts = string.split(".")
      , precision
      , buffer = []
      , formattedNumber
      , format = options.format || "%n"
      , sign = negative ? "-" : ""
    ;

    number = parts[0];
    precision = parts[1];

    while (number.length > 0) {
      buffer.unshift(number.substr(Math.max(0, number.length - 3), 3));
      number = number.substr(0, number.length -3);
    }

    formattedNumber = buffer.join(options.delimiter);

    if (options.strip_insignificant_zeros && precision) {
      precision = precision.replace(/0+$/, "");
    }

    if (options.precision > 0 && precision) {
      formattedNumber += options.separator + precision;
    }

    if (options.sign_first) {
      format = "%s" + format;
    }
    else {
      format = format.replace("%n", "%s%n");
    }

    formattedNumber = format
      .replace("%u", options.unit)
      .replace("%n", formattedNumber)
      .replace("%s", sign)
    ;

    return formattedNumber;
  };

  // Format currency with localization rules.
  // The options will be retrieved from the `number.currency.format` and
  // `number.format` scopes, in that order.
  //
  // Any missing option will be retrieved from the `I18n.toNumber` defaults and
  // the following options:
  //
  // - `unit`: `"$"`
  // - `precision`: `2`
  // - `format`: `"%u%n"`
  // - `delimiter`: `","`
  // - `separator`: `"."`
  //
  // You can also override these options by providing the `options` argument.
  //
  I18n.toCurrency = function(number, options) {
    options = this.prepareOptions(
        options
      , this.lookup("number.currency.format")
      , this.lookup("number.format")
      , CURRENCY_FORMAT
    );

    return this.toNumber(number, options);
  };

  // Localize several values.
  // You can provide the following scopes: `currency`, `number`, or `percentage`.
  // If you provide a scope that matches the `/^(date|time)/` regular expression
  // then the `value` will be converted by using the `I18n.toTime` function.
  //
  // It will default to the value's `toString` function.
  //
  I18n.localize = function(scope, value, options) {
    options || (options = {});

    switch (scope) {
      case "currency":
        return this.toCurrency(value);
      case "number":
        scope = this.lookup("number.format");
        return this.toNumber(value, scope);
      case "percentage":
        return this.toPercentage(value);
      default:
        var localizedValue;

        if (scope.match(/^(date|time)/)) {
          localizedValue = this.toTime(scope, value);
        } else {
          localizedValue = value.toString();
        }

        return this.interpolate(localizedValue, options);
    }
  };

  // Parse a given `date` string into a JavaScript Date object.
  // This function is time zone aware.
  //
  // The following string formats are recognized:
  //
  //    yyyy-mm-dd
  //    yyyy-mm-dd[ T]hh:mm::ss
  //    yyyy-mm-dd[ T]hh:mm::ss
  //    yyyy-mm-dd[ T]hh:mm::ssZ
  //    yyyy-mm-dd[ T]hh:mm::ss+0000
  //    yyyy-mm-dd[ T]hh:mm::ss+00:00
  //    yyyy-mm-dd[ T]hh:mm::ss.123Z
  //
  I18n.parseDate = function(date) {
    var matches, convertedDate, fraction;
    // we have a date, so just return it.
    if (typeof(date) == "object") {
      return date;
    };

    matches = date.toString().match(/(\d{4})-(\d{2})-(\d{2})(?:[ T](\d{2}):(\d{2}):(\d{2})([\.,]\d{1,3})?)?(Z|\+00:?00)?/);

    if (matches) {
      for (var i = 1; i <= 6; i++) {
        matches[i] = parseInt(matches[i], 10) || 0;
      }

      // month starts on 0
      matches[2] -= 1;

      fraction = matches[7] ? 1000 * ("0" + matches[7]) : null;

      if (matches[8]) {
        convertedDate = new Date(Date.UTC(matches[1], matches[2], matches[3], matches[4], matches[5], matches[6], fraction));
      } else {
        convertedDate = new Date(matches[1], matches[2], matches[3], matches[4], matches[5], matches[6], fraction);
      }
    } else if (typeof(date) == "number") {
      // UNIX timestamp
      convertedDate = new Date();
      convertedDate.setTime(date);
    } else if (date.match(/([A-Z][a-z]{2}) ([A-Z][a-z]{2}) (\d+) (\d+:\d+:\d+) ([+-]\d+) (\d+)/)) {
      // This format `Wed Jul 20 13:03:39 +0000 2011` is parsed by
      // webkit/firefox, but not by IE, so we must parse it manually.
      convertedDate = new Date();
      convertedDate.setTime(Date.parse([
        RegExp.$1, RegExp.$2, RegExp.$3, RegExp.$6, RegExp.$4, RegExp.$5
      ].join(" ")));
    } else if (date.match(/\d+ \d+:\d+:\d+ [+-]\d+ \d+/)) {
      // a valid javascript format with timezone info
      convertedDate = new Date();
      convertedDate.setTime(Date.parse(date));
    } else {
      // an arbitrary javascript string
      convertedDate = new Date();
      convertedDate.setTime(Date.parse(date));
    }

    return convertedDate;
  };

  // Formats time according to the directives in the given format string.
  // The directives begins with a percent (%) character. Any text not listed as a
  // directive will be passed through to the output string.
  //
  // The accepted formats are:
  //
  //     %a  - The abbreviated weekday name (Sun)
  //     %A  - The full weekday name (Sunday)
  //     %b  - The abbreviated month name (Jan)
  //     %B  - The full month name (January)
  //     %c  - The preferred local date and time representation
  //     %d  - Day of the month (01..31)
  //     %-d - Day of the month (1..31)
  //     %H  - Hour of the day, 24-hour clock (00..23)
  //     %-H - Hour of the day, 24-hour clock (0..23)
  //     %I  - Hour of the day, 12-hour clock (01..12)
  //     %-I - Hour of the day, 12-hour clock (1..12)
  //     %m  - Month of the year (01..12)
  //     %-m - Month of the year (1..12)
  //     %M  - Minute of the hour (00..59)
  //     %-M - Minute of the hour (0..59)
  //     %p  - Meridian indicator (AM  or  PM)
  //     %S  - Second of the minute (00..60)
  //     %-S - Second of the minute (0..60)
  //     %w  - Day of the week (Sunday is 0, 0..6)
  //     %y  - Year without a century (00..99)
  //     %-y - Year without a century (0..99)
  //     %Y  - Year with century
  //     %z  - Timezone offset (+0545)
  //
  I18n.strftime = function(date, format) {
    var options = this.lookup("date")
      , meridianOptions = I18n.meridian()
    ;

    if (!options) {
      options = {};
    }

    options = this.prepareOptions(options, DATE);

    if (isNaN(date.getTime())) {
      throw new Error('I18n.strftime() requires a valid date object, but received an invalid date.');
    }

    var weekDay = date.getDay()
      , day = date.getDate()
      , year = date.getFullYear()
      , month = date.getMonth() + 1
      , hour = date.getHours()
      , hour12 = hour
      , meridian = hour > 11 ? 1 : 0
      , secs = date.getSeconds()
      , mins = date.getMinutes()
      , offset = date.getTimezoneOffset()
      , absOffsetHours = Math.floor(Math.abs(offset / 60))
      , absOffsetMinutes = Math.abs(offset) - (absOffsetHours * 60)
      , timezoneoffset = (offset > 0 ? "-" : "+") +
          (absOffsetHours.toString().length < 2 ? "0" + absOffsetHours : absOffsetHours) +
          (absOffsetMinutes.toString().length < 2 ? "0" + absOffsetMinutes : absOffsetMinutes)
    ;

    if (hour12 > 12) {
      hour12 = hour12 - 12;
    } else if (hour12 === 0) {
      hour12 = 12;
    }

    format = format.replace("%a", options.abbr_day_names[weekDay]);
    format = format.replace("%A", options.day_names[weekDay]);
    format = format.replace("%b", options.abbr_month_names[month]);
    format = format.replace("%B", options.month_names[month]);
    format = format.replace("%d", padding(day));
    format = format.replace("%e", day);
    format = format.replace("%-d", day);
    format = format.replace("%H", padding(hour));
    format = format.replace("%-H", hour);
    format = format.replace("%I", padding(hour12));
    format = format.replace("%-I", hour12);
    format = format.replace("%m", padding(month));
    format = format.replace("%-m", month);
    format = format.replace("%M", padding(mins));
    format = format.replace("%-M", mins);
    format = format.replace("%p", meridianOptions[meridian]);
    format = format.replace("%S", padding(secs));
    format = format.replace("%-S", secs);
    format = format.replace("%w", weekDay);
    format = format.replace("%y", padding(year));
    format = format.replace("%-y", padding(year).replace(/^0+/, ""));
    format = format.replace("%Y", year);
    format = format.replace("%z", timezoneoffset);

    return format;
  };

  // Convert the given dateString into a formatted date.
  I18n.toTime = function(scope, dateString) {
    var date = this.parseDate(dateString)
      , format = this.lookup(scope)
    ;

    if (date.toString().match(/invalid/i)) {
      return date.toString();
    }

    if (!format) {
      return date.toString();
    }

    return this.strftime(date, format);
  };

  // Convert a number into a formatted percentage value.
  I18n.toPercentage = function(number, options) {
    options = this.prepareOptions(
        options
      , this.lookup("number.percentage.format")
      , this.lookup("number.format")
      , PERCENTAGE_FORMAT
    );

    return this.toNumber(number, options);
  };

  // Convert a number into a readable size representation.
  I18n.toHumanSize = function(number, options) {
    var kb = 1024
      , size = number
      , iterations = 0
      , unit
      , precision
    ;

    while (size >= kb && iterations < 4) {
      size = size / kb;
      iterations += 1;
    }

    if (iterations === 0) {
      unit = this.t("number.human.storage_units.units.byte", {count: size});
      precision = 0;
    } else {
      unit = this.t("number.human.storage_units.units." + SIZE_UNITS[iterations]);
      precision = (size - Math.floor(size) === 0) ? 0 : 1;
    }

    options = this.prepareOptions(
        options
      , {unit: unit, precision: precision, format: "%n%u", delimiter: ""}
    );

    return this.toNumber(size, options);
  };

  I18n.getFullScope = function(scope, options) {
    options = this.prepareOptions(options);

    // Deal with the scope as an array.
    if (scope.constructor === Array) {
      scope = scope.join(this.defaultSeparator);
    }

    // Deal with the scope option provided through the second argument.
    //
    //    I18n.t('hello', {scope: 'greetings'});
    //
    if (options.scope) {
      scope = [options.scope, scope].join(this.defaultSeparator);
    }

    return scope;
  };
  /**
   * Merge obj1 with obj2 (shallow merge), without modifying inputs
   * @param {Object} obj1
   * @param {Object} obj2
   * @returns {Object} Merged values of obj1 and obj2
   *
   * In order to support ES3, `Object.prototype.hasOwnProperty.call` is used
   * Idea is from:
   * https://stackoverflow.com/questions/8157700/object-has-no-hasownproperty-method-i-e-its-undefined-ie8
   */
  I18n.extend = function ( obj1, obj2 ) {
    var extended = {};
    var prop;
    for (prop in obj1) {
      if (Object.prototype.hasOwnProperty.call(obj1, prop)) {
        extended[prop] = obj1[prop];
      }
    }
    for (prop in obj2) {
      if (Object.prototype.hasOwnProperty.call(obj2, prop)) {
        extended[prop] = obj2[prop];
      }
    }
    return extended;
  };

  // Set aliases, so we can save some typing.
  I18n.t = I18n.translate;
  I18n.l = I18n.localize;
  I18n.p = I18n.pluralize;

  return I18n;
}));