feat: Allow to get OpenFoodFactsCountry from countryCode

[M123-dev]

No description provided.

[monsieurtanuki]

Does not work for an unknown code: crashes, instead of an expected null.
firstWhere is not adequate, as it never returns null.
Your previous syntax was correct (it's just that the return; was useless).

[M123-dev]

Yes I know that it theoretically worked but it didn't make sense since the extension only worked for specific values of the enum, not for the enum itself, so there you would have to write OpenFoodFactsCountry.FRANCE.fromCountryCode('de') which would return germany, that's why I moved it and now the structure is similar to the one in the OpenFoodFactsLanguage.

Regarding the null problem, it's not possible to return null from orElse so we could either add a UNKNOW value to the enum as in the OpenFoodFactsLanguage but I would rather just switch back to the old forEach loop.

[monsieurtanuki]

I see, static methods don't seem to be allowed in extensions.

Similarly to what you wrote initially, and which seems to work:

class CountryHelper {
  static OpenFoodFactsCountry? fromJson(String? code) {
    OpenFoodFactsCountry? result;
    OpenFoodFactsCountry.values.forEach((final OpenFoodFactsCountry key) {
      if (key.iso2Code == code) {
        result = key;
      }
    });
    return result;
  }
}

[monsieurtanuki]

Or even better (I don't find the dart map methods always 100% relevant):

class CountryHelper {
  static OpenFoodFactsCountry? fromJson(String? code) {
    if (code == null) {
      return null;
    }
    for (final OpenFoodFactsCountry key in OpenFoodFactsCountry.values) {
      if (key.iso2Code == code) {
        return key;
      }
    }
    return null;
  }
}

[M123-dev]

Changed it, good suggestion

[monsieurtanuki]

Should be OK now @M123-dev!

[M123-dev]

Thanks @monsieurtanuki