Typescript type generation for i18n files.

This CLI tool was used to help with type-safety while using i18n translations. Especially designed for react-i18next while using HttpApi

Install

Install as dev dependency:

npm install -D @morabotti/i18n-types-generator-cli

Or with yarn:

yarn add -D @morabotti/i18n-types-generator-cli

Usage

You can run the the cli with i18n-types-generator command. You can use nodemon to watch for changes in locales file and hot build the latest type file.

Example npm scripts:

"scripts": {
  "i18n": "i18n-types-generator -l en -p \"locales/{{lang}}/{{ns}}.json\" -o \"src/generated/translations.generated.ts\"",
  "i18n:watch": "nodemon --exec \"npm run i18n\" --watch locales"
},

CLI tool accepts following option parameters:

Options:
  --help            Show help                       [boolean]
  --version         Show version number             [boolean]
  -p, --path        Path to translations            [string] [required]
  -o, --output      Path to output file             [string] [required]
  -l, --lang        Default language                [string]
  -d, --delimiter   Delimiter between ns & key      [string] [default: ":"]

Option	Description	Example value	Required/Optional
Path	Define path to source files. {{ns}} is currently required.	locales/{{lang}}/{{ns}}.json	Required
Output	Path to generated typescript file. This file should be included in version control.	src/generated/translations.generated.ts	Required
Lang	Default language that has the "most" values. This language will construct the types/enums.	en	Optional
Delimiter	Delimiter for namespace mapping.	:	Optional (default: ":")

Example with react-i18next hook

import { KeyPrefix, useTranslation, UseTranslationResponse } from 'react-i18next';
import { TranslationsMapping, Namespace } from '@generated/translations.generated';

interface ResponseContext<T extends Namespace[]>
  extends Omit<UseTranslationResponse<T, KeyPrefix<T>>, 't'> {
  t: (key: TranslationsMapping<T>, values?: Record<string, string | number>) => string;
}

export const useLanguage = <T extends Namespace[]> (
  namespaces?: T
): ResponseContext<T> => {
  return useTranslation(namespaces) as ResponseContext<T>;
};

With this custom hook, you will every single time have strongly typed paths. No more typos.

Whats being exported

All of the enum keys/types are converted to PascalCase

• Enum Language: Collection of languages. Gotten with {{lang}} variable in cli option --path.
• Enum Namespace: Collection of namespaces.
• List of type keys *Keys: Keys types contain all of the key paths for specific namespace.
• Type TranslationKey: All of the *Keys types combined.
• Type TranslationMapping: Way to select certain *Keys with Namespace. Only Singular Namespace.
• Type TranslationMapping<X extends Namespace[]>: Way to select multiple *Keys with list of Namespace's. If there are multiple namespaces, Keys include namespace e.g. namespace:${NamespaceKeys}.

Development

Install the bin npm install -g . Or use npm run start with npm link/npm unlink Run with i18n-types-generator -p "/locales/{{lang}}/{{ns}}.json" -o "/example.generated.ts" format or simply with npm run start

TODO

• Unit/Type testing for generated file
• Support for different formatting