Type-graphql: Is annotation Field( type => Map) supported?

[martiro]

Hi everyone,
I'm trying to implement i18n feature on my backend and I need to store different translations for fields that require to be localized (ex: name, description,...).
In my mind I though to design a field able to store a Map in order to provide the front-end a json like this:

{
    name: { en: "Book", de:"Buch", it="Libro"}
}   

In this way, the front-end will be able to get desired translation immediately simply calling:

var bookName = name[userLanguage]; //where user language is a context variable

I tryed to use the annotation @Field(type => Map) but I get the following error:

UnhandledPromiseRejectionWarning: Error: Cannot determine GraphQL output type for name
    at Function.getGraphQLOutputType (R:\Progetti\BiteCode\kaleidos-backend\node_modules\type-graphql\dist\schema\schema-generator.js:394:19)
    at objectType.fields.reduce (R:\Progetti\BiteCode\kaleidos-backend\node_modules\type-graphql\dist\schema\schema-generator.js:174:44)
    at Array.reduce (<anonymous>)

Since it seems that the usage of type "Map" is not supported, what is the best way to achieve this result?

Thanks in advance
Roberto

[MichalLytek]

You have to explicitly type all possible property names:

@ObjectType()
class Translations {
  @Field()
  en: string;

  @Field()
  de: string;

  @Field()
  it: string;
}

And then use such construct in your base type:

@ObjectType()
class Book{
  @Field(type => Translations)
  name: Translations;
}

Or if you don't need all translation on client at once, you can just ask for a translated string:

enum Language {
  EN
  DE
  IT
}

query {
  books {
    id
    pagesCount
    name(language: EN)
  }
}

In that case you need to do the name[userLanguage] mapping from db entity column to returned string in a field resolver.

[martiro]

Thanks a lot. This solution can work for me.

[MichalLytek]

Closing for a housekeeping purposes 🔒

[kemicofa]

It would be extremely tedious to type out all the possibilities. I would love to have this feature 👍

Does there exist a temporary solution for this to work?

[MichalLytek]

It would be extremely tedious to type out all the possibilities

Welcome in the GraphQL world where everything has to be explicitly listed 👋

If you don't care about a type-safety and ability to select specific fields, you can retrieve the whole structure at once by two ways:

• using GraphQLJSON scalar type
• defining a key-value type and return an array of key-value object (e.g. using Object.entiries)