Elm I18Next Code Generation

An elm-codegen library for creating type-safe helper methods for the excellent ChristophP/elm-i18next package.

If you have a large Elm application in a business setting, you should strongly consider supporting internationalization even if you aren't considering adding extra languages to your app. Your project manager who would much rather change a line in a JSON file than put another 1-point ticket into your sprint will thank you for it.

Elm Codegen Usage

In your project that consumes the generated code, you should elm install ChristophP/elm-i18next. This library generates code for usage with ChristophP/elm-i18next.

npx @abradley2/elm-i18next-gen --output=generated --translations=relative/path/to/translations.json

This will create a directory "generated" containing a Language.elm file and a Translations.elm file, along with Translations sub modules based on the structure of your translations file.

A translations file like should look something like this, conforming to the I18Next V2 specification:

{
   "general greeting": "Hello there",
   "personal greeting": "Hello {{name}}"
}

This will generate the following:

generalGreeting : List I18Next.Translations -> String
generalGreeting translations =
    I18Next.tf translations "generalGreeting"


personalGreeting : List I18Next.Translations -> { name : String } -> String
personalGreeting translations replacements =
    I18Next.trf
        translations
        I18Next.Curly
        "personalGreeting"
        [ ( "name", replacements.name ) ]

-and a default implementation of I18Next.Translations in the sibling Language.elm module.

defaultLanguage : I18Next.Translations
defaultLanguage =
    I18Next.fromTree
         [ ( ""
           , I18Next.object 
                [ ( "generalGreeting", I18Next.string "Hello there" ) 
                , ( "personalGreeting", I18Next.string "Hello {{name}}" )
                ]
           )
         ]

You can also nest translations by page as the I18Next V2 specification allows.

{
   "home": { ... },
   "login": { ... }
}

This will create the sub-modules in the Translations directory.

Recommended Pattern

It is recommended that you only run this codegen for a single default language. Part of the output includes a defaultLanguage export of the I18Next.Translations type. For all your translations that are not part of your default language, use I18Next.translationsDecoder as you normally would.

Thanks

This library is largely based upon the work done by Yoni Gibbs on elm-i8next-gen