Now, it's time to generate a set of Dart libraries that contain translated versions of our messages—one per locale from the ARB files prepared before. We use the generate_from_arb program from the intl package:

pub run intl:generate_from_arb --output-dir=web web/registration_form.dart web/translate_en.arb web/translate_de.arb

The program generates the message_de.dart, message_en.dart, and messages_all.dart files in the specified web directory. Each message_<locale_tag>.dart file contains the MessageLookup class that implements MessageLookupByLibrary. The MessageLookup class has a getter method localeName, a set of static functions that are returned translated on the specific locale text messages, and final constant messages that contain the name of all the static methods. The messages_all.dart file combines all the lookups in one place to make them available for the localization code from the Intl library. The single available public method of the message_all library is initializeMessages, as shown in the following code:

Future initializeMessages(String localeName)

This method should be called first before using the specified localeName method. Let's change our code to make the German locale available by default. All we need to do is import the messages_all.dart file to our project and add initializeMessages in the main method, as shown in the following code:

import 'messages_all.dart';
…
void main() {
  initializeMessages('de').then((_) {
    Intl.defaultLocale = 'de';
    querySelector("#formHead").text = formHead();
    querySelector("#firstNameLbl").text = firstNameLbl();
    querySelector("#lastNameLbl").text = lastNameLbl();
    querySelector("#genderLbl").text = genderLbl();
    querySelector("#maleLbl").text = maleLbl();
    querySelector("#femaleLbl").text = femaleLbl();
    (querySelector("#registerBtn") as InputElement)
      .value = registerBtn();
    BidiFormatter bidiFormatter = new BidiFormatter.UNKNOWN();
    querySelector("#copyrightLbl").text = 
      bidiFormatter.wrapWithUnicode(copyrightLbl());
  });
}

In the preceding code, we specified the German locale when we initialized the messages as default. Now, open the index.html file in the browser to see the correct translation of our form in the German locale: