Implementation

You should follow Unicode BCP47 Locale Identifier, for example the valid locale code should be: zh-Hans-CN, see https://www.unicode.org/reports/tr35/ for more details.

About the data structure

Script code shuold be combined with a two-letter language code

Script codes, such as Hans and Hant, are used only in Chinese languages currently. The script code should be combined with a two-letter language code, for example:

zh_Hant

Abount zh_Hans

Since we use simplified Chinese as the default, Hans should not be used. Therefore, there is no zh_Hans or zh_Hans_[region]. For example, zh_Hans should be referred to as zh, and zh_Hans_SG should be referred to as zh_SG.

Abount zh_Hant_[region]

TW,HK and MO must have the script code Hant, For example, these are not allowed as the keys in our data:

zh_TW
zh_HK
zh_MO

All regions allow Hant, for example:

zh_Hant_US

Language

A language consists of a language code and a script code, but it should not include the region code.

For example:

zh //generic simplified Chinese
zh_Hant //generic traditional Chinese
en_US
fr_FR

Region

A region code is composed of two capitalized letters, such as CN.

See:
ISO 3166-1 alpha-2

Files

languages.json

The key of each language item is the language code, optionally followed by the script code if needed and when the language is Chinese.

Example:

{
  "en": {
    "value": "English"
  },
  "zh": {
    "value": "简体中文"
  },
  "zh_Hant": {
    "value": "繁體中文",
    "TW": "正體中文"
  },
  "sv": {
    "value": "Svenska"
  },
  "de": {
    "value": "Deutsch"
  }
}

regions.json

A region consists of l10n and calling_code.

The key of each l10n is the language code, optionally followed by the region code if needed.

Example:

{
  "CN": {
    "l10n": {
      "en": "China",
      "zh": "中国",
      "zh_Hant": "中國",
      "sv": "Kina"
    },
    "calling_code": "86"
  },
  "LA": {
    "l10n": {
      "en": "Laos",
      "zh": "老挝",
      "zh_Hant": "老撾",
      "zh_SG": "寮国",
      "zh_Hant_TW": "寮國"
    },
    "calling_code": "856"
  }
}

Implementations

See: https://github.com/hanlogy/dart_packages/tree/master/locale

Resources

https://en.wikipedia.org/wiki/ISO_3166-1