GraphQL

When using GraphQL nestjs-i18n works out of the box in most cases. With normal requests you can add headers etc. so the resolvers still work like you would expect. But when using GraphQL subscriptions this requires additional steps.

To fix this change your GraphQLModule configuration.

src/app.module.ts

  GraphQLModule.forRoot<ApolloDriverConfig>({
    driver: ApolloDriver,
    subscriptions: {
      'graphql-ws': true,
    },
    typePaths: ['*/**/*.graphql'],
+   context: (ctx) => ctx,
    path: '/graphql',
  })

caution

It's recommened to use graphql-ws instead of subscriptions-transport-ws (read more). If you're still using subscriptions-transport-ws you should re-configure your GraphQLModule.

src/app.module.ts

  GraphQLModule.forRoot<ApolloDriverConfig>({
    driver: ApolloDriver,
    subscriptions: {
+     'subscriptions-transport-ws': {
+       onConnect: (params) => ({ connectionParams: params }),
+       path: '/graphql'
      }
    },
    typePaths: ['*/**/*.graphql'],
+   context: (ctx) => ctx,
    path: '/graphql',
  })

After that use the following GraphQLWebsocketResolver resolver.

src/app.module.ts

  I18nModule.forRoot({
    fallbackLanguage: 'en',
    loaderOptions: {
      path: path.join(__dirname, '/i18n/'),
      watch: true,
    },
    resolvers: [
+     GraphQLWebsocketResolver,
      { use: QueryResolver, options: ['lang'] },
      AcceptLanguageResolver,
    ],
  })