module I18n::Base

Gets I18n configuration object.

# File lib/i18n.rb, line 57
def config
  Thread.current[:i18n_config] ||= I18n::Config.new
end

Sets I18n configuration object.

# File lib/i18n.rb, line 62
def config=(value)
  Thread.current[:i18n_config] = value
end

Tells the backend to load translations now. Used in situations like the Rails production environment. Backends can implement whatever strategy is useful.

# File lib/i18n.rb, line 91
def eager_load!
  config.backend.eager_load!
end

Raises an InvalidLocale exception when the passed locale is not available.

# File lib/i18n.rb, line 380
def enforce_available_locales!(locale)
  if locale != false && config.enforce_available_locales
    raise I18n::InvalidLocale.new(locale) if !locale_available?(locale)
  end
end

Returns true if a translation exists for a given key, otherwise returns false.

# File lib/i18n.rb, line 265
def exists?(key, _locale = nil, locale: _locale, **options)
  locale ||= config.locale
  raise Disabled.new('exists?') if locale == false
  raise I18n::ArgumentError if (key.is_a?(String) && key.empty?) || key.nil?

  config.backend.exists?(locale, key, options)
end

Returns an array of interpolation keys for the given translation key

Examples

Suppose we have the following:

I18n.t 'example.zero' == 'Zero interpolations'
I18n.t 'example.one' == 'One interpolation %{foo}'
I18n.t 'example.two' == 'Two interpolations %{foo} %{bar}'
I18n.t 'example.three' == ['One %{foo}', 'Two %{bar}', 'Three %{baz}']
I18n.t 'example.one', locale: :other == 'One interpolation %{baz}'

Then we can expect the following results:

I18n.interpolation_keys('example.zero') #=> []
I18n.interpolation_keys('example.one') #=> ['foo']
I18n.interpolation_keys('example.two') #=> ['foo', 'bar']
I18n.interpolation_keys('example.three') #=> ['foo', 'bar', 'baz']
I18n.interpolation_keys('one', scope: 'example', locale: :other) #=> ['baz']
I18n.interpolation_keys('does-not-exist') #=> []
I18n.interpolation_keys('example') #=> []

# File lib/i18n.rb, line 254
def interpolation_keys(key, **options)
  raise I18n::ArgumentError if !key.is_a?(String) || key.empty?

  return [] unless exists?(key, **options.slice(:locale, :scope))

  translation = translate(key, **options.slice(:locale, :scope))
  interpolation_keys_from_translation(translation)
    .flatten.compact
end

Returns true when the passed locale, which can be either a String or a Symbol, is in the list of available locales. Returns false otherwise.

# File lib/i18n.rb, line 375
def locale_available?(locale)
  I18n.config.available_locales_set.include?(locale)
end

Localizes certain objects, such as dates and numbers to local formatting.

# File lib/i18n.rb, line 335
def localize(object, locale: nil, format: nil, **options)
  locale ||= config.locale
  raise Disabled.new('l') if locale == false
  enforce_available_locales!(locale)

  format ||= :default
  config.backend.localize(locale, object, format, options)
end

Merges the given locale, key and scope into a single array of keys. Splits keys that contain dots into multiple keys. Makes sure all keys are Symbols.

# File lib/i18n.rb, line 363
def normalize_keys(locale, key, scope, separator = nil)
  separator ||= I18n.default_separator

  [
    *normalize_key(locale, separator),
    *normalize_key(scope, separator),
    *normalize_key(key, separator)
  ]
end

Tells the backend to reload translations. Used in situations like the Rails development environment. Backends can implement whatever strategy is useful.

# File lib/i18n.rb, line 83
def reload!
  config.clear_available_locales_set
  config.backend.reload!
end

Translates, pluralizes and interpolates a given key using a given locale, scope, and default, as well as interpolation values.

LOOKUP

Translation data is organized as a nested hash using the upper-level keys as namespaces. E.g., ActionView ships with the translation: :date => {:formats => {:short => "%b %d"}}.

Translations can be looked up at any level of this hash using the key argument and the scope option. E.g., in this example I18n.t :date returns the whole translations hash {:formats => {:short => "%b %d"}}.

Key can be either a single key or a dot-separated key (both Strings and Symbols work). E.g., the short format can be looked up using both:

I18n.t 'date.formats.short'
I18n.t :'date.formats.short'

Scope can be either a single key, a dot-separated key or an array of keys or dot-separated keys. Keys and scopes can be combined freely. So these examples will all look up the same short date format:

I18n.t 'date.formats.short'
I18n.t 'formats.short', :scope => 'date'
I18n.t 'short', :scope => 'date.formats'
I18n.t 'short', :scope => %w(date formats)

INTERPOLATION

Translations can contain interpolation variables which will be replaced by values passed to translate as part of the options hash, with the keys matching the interpolation variable names.

E.g., with a translation :foo => "foo %{bar}" the option value for the key bar will be interpolated into the translation:

I18n.t :foo, :bar => 'baz' # => 'foo baz'

PLURALIZATION

Translation data can contain pluralized translations. Pluralized translations are arrays of singular/plural versions of translations like ['Foo', 'Foos'].

Note that I18n::Backend::Simple only supports an algorithm for English pluralization rules. Other algorithms can be supported by custom backends.

This returns the singular version of a pluralized translation:

I18n.t :foo, :count => 1 # => 'Foo'

These both return the plural version of a pluralized translation:

I18n.t :foo, :count => 0 # => 'Foos'
I18n.t :foo, :count => 2 # => 'Foos'

The :count option can be used both for pluralization and interpolation. E.g., with the translation :foo => ['%{count} foo', '%{count} foos'], count will be interpolated to the pluralized translation:

I18n.t :foo, :count => 1 # => '1 foo'

DEFAULTS

This returns the translation for :foo or default if no translation was found:

I18n.t :foo, :default => 'default'

This returns the translation for :foo or the translation for :bar if no translation for :foo was found:

I18n.t :foo, :default => :bar

Returns the translation for :foo or the translation for :bar or default if no translations for :foo and :bar were found.

I18n.t :foo, :default => [:bar, 'default']

BULK LOOKUP

This returns an array with the translations for :foo and :bar.

I18n.t [:foo, :bar]

Can be used with dot-separated nested keys:

I18n.t [:'baz.foo', :'baz.bar']

Which is the same as using a scope option:

I18n.t [:foo, :bar], :scope => :baz

LAMBDAS

Both translations and defaults can be given as Ruby lambdas. Lambdas will be called and passed the key and options.

E.g. assuming the key :salutation resolves to:

lambda { |key, options| options[:gender] == 'm' ? "Mr. #{options[:name]}" : "Mrs. #{options[:name]}" }

Then I18n.t(:salutation, :gender => 'w', :name => 'Smith') will result in “Mrs. Smith”.

Note that the string returned by lambda will go through string interpolation too, so the following lambda would give the same result:

lambda { |key, options| options[:gender] == 'm' ? "Mr. %{name}" : "Mrs. %{name}" }

It is recommended to use/implement lambdas in an “idempotent” way. E.g. when a cache layer is put in front of I18n.translate it will generate a cache key from the argument values passed to translate. Therefore your lambdas should always return the same translations/values per unique combination of argument values.

Ruby 2.7+ keyword arguments warning

This method uses keyword arguments. There is a breaking change in ruby that produces warning with ruby 2.7 and won’t work as expected with ruby 3.0 The “hash” parameter must be passed as keyword argument.

Good:

I18n.t(:salutation, :gender => 'w', :name => 'Smith')
I18n.t(:salutation, **{ :gender => 'w', :name => 'Smith' })
I18n.t(:salutation, **any_hash)

Bad:

I18n.t(:salutation, { :gender => 'w', :name => 'Smith' })
I18n.t(:salutation, any_hash)

# File lib/i18n.rb, line 211
def translate(key = nil, throw: false, raise: false, locale: nil, **options) # TODO deprecate :raise
  locale ||= config.locale
  raise Disabled.new('t') if locale == false
  enforce_available_locales!(locale)

  backend = config.backend

  if key.is_a?(Array)
    key.map do |k|
      translate_key(k, throw, raise, locale, backend, options)
    end
  else
    translate_key(key, throw, raise, locale, backend, options)
  end
end

Wrapper for translate that adds :raise => true. With this option, if no translation is found, it will raise I18n::MissingTranslationData

# File lib/i18n.rb, line 230
def translate!(key, **options)
  translate(key, **options, raise: true)
end

Transliterates UTF-8 characters to ASCII. By default this method will transliterate only Latin strings to an ASCII approximation:

I18n.transliterate("Ærøskøbing")
# => "AEroskobing"

I18n.transliterate("日本語")
# => "???"

It’s also possible to add support for per-locale transliterations. I18n expects transliteration rules to be stored at i18n.transliterate.rule.

Transliteration rules can either be a Hash or a Proc. Procs must accept a single string argument. Hash rules inherit the default transliteration rules, while Procs do not.

Examples

Setting a Hash in <locale>.yml:

i18n:
  transliterate:
    rule:
      ü: "ue"
      ö: "oe"

Setting a Hash using Ruby:

store_translations(:de, i18n: {
                     transliterate: {
                       rule: {
                         'ü' => 'ue',
                         'ö' => 'oe'
                       }
                     }
                   })

Setting a Proc:

translit = lambda {|string| MyTransliterator.transliterate(string) }
store_translations(:xx, :i18n => {:transliterate => {:rule => translit})

Transliterating strings:

I18n.locale = :en
I18n.transliterate("Jürgen") # => "Jurgen"
I18n.locale = :de
I18n.transliterate("Jürgen") # => "Juergen"
I18n.transliterate("Jürgen", :locale => :en) # => "Jurgen"
I18n.transliterate("Jürgen", :locale => :de) # => "Juergen"

# File lib/i18n.rb, line 324
def transliterate(key, throw: false, raise: false, locale: nil, replacement: nil, **options)
  locale ||= config.locale
  raise Disabled.new('transliterate') if locale == false
  enforce_available_locales!(locale)

  config.backend.transliterate(locale, key, replacement)
rescue I18n::ArgumentError => exception
  handle_exception((throw && :throw || raise && :raise), exception, locale, key, options)
end

Executes block with given I18n.locale set.

# File lib/i18n.rb, line 346
def with_locale(tmp_locale = nil)
  if tmp_locale == nil
    yield
  else
    current_locale = self.locale
    self.locale = tmp_locale
    begin
      yield
    ensure
      self.locale = current_locale
    end
  end
end