Generates the lib\src\constants.dart file for the flutter_font_picker package.

Should be used by flutter_font_picker package maintainers to update the lib\src\constants.dart file when the google_fonts package is updated.

Usage:

A) Get the complete list of Google Fonts, their variants, languages, and weights. Two ways to achieve that:

• Go to https://developers.google.com/fonts/docs/developer_api and click the blue 'EXECUTE' button on the right. Grab the JSON output that appears, and paste it into a new file in this folder (ie. api_output.json).

• Use your own private Google Fonts API key and supply that as a command line argument to the update_constants.dart tool.

NOTE 1: The google_fonts Dart package supports only a subset of the complete list. This is automatically retrieved from https://raw.githubusercontent.com/material-foundation/flutter-packages/main/packages/google_fonts/generator/families_supported.

NOTE 2: Pass the --legacylanguages (or -l) command line option to keep the previous versions list of languages. There is quite a large list of languages now and the current version (as of 1.1.3) does not include most of them.

B) Execute the update_constants.dart generator tool. This will create a new constants.dart file in the current directory, along with info comparing it to the previous file.

C) Copy the new constants.dart file into the \lib\src\constants\ directory to overwrite the previous version.

Each time we update the Google Fonts list, we should publish a new minor version of the flutter_font_picker package.

Examples:

I) Using a previously downloaded Google Fonts JSON file:

cd generator
dart run update_constants.dart -i api_output_feb_22_23.json

II) Using your private Google Fonts API key:

cd generator
dart run update_constants.dart --apikey YOUR_SECRET_API_KEY

III) Display the help and command line usage instructions:

cd generator
dart run update_constants.dart -h

IV) Example of entire process of creating new constants.dart file and replacing the old (using your private Google Fonts API key):

cd generator
dart run update_constants.dart --apikey YOUR_SECRET_API_KEY
cp constants.dart ../lib/src/constants/constants.dart

NOTE: Limit the list of languages to those of the previous version of constants.dart using the --legacylanguages (or -l) command line argument.