Lingual i18n-check

i18n-check validates your ICU and i18next translation files and checks for missing and broken translations. It compares the defined source language with all target translation files and finds inconsistencies between source and target files. You can run these checks as a pre-commit hook or on the CI depending on your use-case and setup.

Table of Contents

• Installation
• General Usage
• CLI Options
• Examples
  • Single folder
  • Folder per locale
  • Folder per locale with multiple files
• Github Action
• API
• Development
• Links

Installation

Using yarn:

yarn add --dev @lingual/i18n-check

Using npm:

npm install --save-dev @lingual/i18n-check

Using pnpm:

pnpm add --save-dev @lingual/i18n-check

After the installation, i18n-check can either be accessed via defining a command in the package.json file or directly in the CLI.

Update your package.json and add a new command:

"scripts": {
    // ...other commands,
    "i18n:check": "i18n-check"
}

Now you can run the i18n:check command directly from the command-line, i.e. yarn i18n:check.

Alternatively you can also access the library directly:

node_modules/.bin/i18n-check

General Usage

For i18n-check to work you need to provide it at a minimum the source locale (--source, -s) for the primary language and the path to the locale translation files (--locales, -l).

Example:

yarn i18n:check -s en-US --locales translations/

Instead of a single source file you can also pass a directory:

yarn i18n:check -s en-US --locales translations/

See the examples for more details.

Options

--locales, -l

With the -l or --locales option you define which folder or multiple folders you want to run the i18n checks against. It is a required option. i18n-check will try to find all target locale files and compare these files against the defined source file(s). Check the example to see how different locale translation files are organised and how they can be addressed.

yarn i18n:check --locales translations/messageExamples -s en-US

--source, -s

With the -s or --source option you define the source locale to compare all target files against. It is a required option. i18n-check will try to find all target locale files and compare these files against the applicable source file(s). Check the examples to see how different locale translation files are organised and how they can be addressed.

yarn i18n:check --locales translations/messageExamples -s en-US

--format, -f

By default i18n-check will validate against any ICU compliant translations. Additionally the i18next format is supported and can be set via the -f or --format option.

There are i18n libraries that have their own specific format, which might not be based on ICU and therefore can not be validated against currently. On a side-note: there might be future support for more specific formats.

Hint: If you want to use the --unused flag, you should provide react-intl as the format. Also see the unused section for more details.

yarn i18n:check --locales translations/i18NextMessageExamples -s en-US -f i18next

--check, -c

By default i18n-check will perform a validation against any missing and/or invalid keys. There are situations where only a specific check should run. By using the -c or --check option you can specify a specific check to run.

The available options are missingKeys, which will check against any missing keys in the target files and invalidKeys will check for invalid keys, where the target translations has a different type then the one defined in the source file.

Check for missing keys:

yarn i18n:check --locales translations/messageExamples -s en-US -c missingKeys

Check for invalid keys:

yarn i18n:check --locales translations/messageExamples -s en-US -c invalidKeys

Check for missing and invalid keys (which is the default):

yarn i18n:check --locales translations/messageExamples -s en-US -c missingKeys,invalidKeys

--unused, -u

This feature is currently only supported for react-intl and is useful if you need to know which keys exist in your translation files but not in your codebase. Via the -u or --unused option you provide a source path to the code, which will be parsed to find all unused keys in the primary target language.

It is important to note that you must also provide the -f or --format option with react-intl as value. See the format section for more information.

yarn i18n:check --locales translations/messageExamples -s en-US -u client/ -f react-intl

--reporter, -r

The standard reporting prints out all the missing or invalid keys. Using the -r or --reporter option enables to override the standard error reporting. Passing the summary option will print a summary of the missing or invalid keys.

yarn i18n:check --locales translations/messageExamples -s en-US -r summary

--exclude, -e

There are situations where we want to exclude a single or multiple files or a single folder or a group of folders. A typical scenario would be that some keys are missing in a specific folder, as they are being work in progress for example. To exclude this or these files/folders you can use the -e or --exclude option. It expects one or more files and/or folders.

To exclude a single file:

yarn i18n:check --locales translations/messageExamples -s en-US -e translations/messageExamples/fr-fr.json

To exclude multiple files provide all files:

yarn i18n:check --locales translations/messageExamples -s en-US -e translations/messageExamples/fr-fr.json translations/messageExamples/de-at.json

To exclude a single folder:

yarn i18n:check --locales translations/folderExamples -s en-US -e translations/folderExamples/fr/*

Alternatively you can exclude multiple folders by providing the folders to be excluded:

yarn i18n:check --locales translations/folderExamples -s en-US -e translations/folderExamples/fr/* translations/folderExample/it/*

The --exclude option also accepts a mix of files and folders, which follows the same pattern as above, i.e. -e translations/folderExamples/fr/* translations/messageExamples/it.json

Examples

i18n-check is able to load and validate against different locale folder structures. Depending on how the locale files are organized, there are different configuration options.

Single folder

If all the locales are organized in a single folder:

locales/
  en-en.json
  de-de.json

Use the t or target option to define the directory that should be checked for target files. With the s or source option you can specify the base/reference file to compare the target files against.

yarn i18n:check --locales locales -s locales/en-us.json

Folder per locale

If the locales are organised as folders containing a single json file:

locales/
  en-US/
    index.json
  de-DE/
    index.json

Define the locales folder as the directory to look for target files.

yarn i18n:check --locales locales -s en-US

Folder per locale with multiple files

If the locales are organised as folders containing multiple json files:

locales/
  en-US/
    one.json
    two.json
    three.json
  de-DE/
    one.json
    two.json
    three.json

Define the locales folder as the directory to look for target files and pass locales/en-US/ as the source option. i18n-check will try to collect all the files in the provided source directory and compare each one against the corresponding files in the target locales.

yarn i18n:check --locales locales -s en-US

Multiple folders containing locales

If the locales are organised as folders containing multiple json files:

- spaceOne
  - locales/
    - en-US/
      - one.json
      - two.json
      - three.json
    - de-DE/
      - one.json
      - two.json
      - three.json
- spaceTwo
  - locales/
    - en-US/
      - one.json
      - two.json
      - three.json
    - de-DE/
      - one.json
      - two.json
      - three.json

Define the locales folder as the directory to look for target files and pass en-US as the source option. i18n-check will try to collect all the files in the provided source directory and compare each one against the corresponding files in the target locales.

yarn i18n:check -l spaceOne spaceTwo -s en-US

As Github Action

We currently do not offer an explicit Github Action you can use out of the box, but if you have i18n-check already installed, you can define your own YAML file. The following example can be seen as a starting point that you can adapt to your current setup:

name: i18n Check
on:
  pull_request:
    branches:
      - main
  push:
    branches:
      - main

jobs:
  i18n-check:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@master

      - name: yarn install & build
        run: |
          yarn install
          yarn build

      - name: yarn i18n-check
        run: |
          yarn i18n-check --locales translations/messageExamples --source en-US

The above workflow will return any missing or invalid keys and the action would fail if missing/invalid keys are found:

API

Aside from using the CLI, i18n-check also exposes a set of check functions that can be accessed programmatically. Start by importing i18n-check:

import * as i18nCheck from "@lingual/i18n-check";

i18nCheck.checkTranslations(source, targets [, options])

checkTranslations expects the base and comparison or target files and returns an object containing the missing and invalid keys. The optional options objects can be provided as a third argument to define the format style via the format property, this is useful if you want to validate i18next specific translations.

import { checkTranslations } from "@lingual/i18n-check";

const options = {
  format: "i18next",
};

const { invalidKeys, missingKeys } = checkTranslations(
  source,
  targets,
  options
);

Additionally the options object enables to also define which checks should run via the checks property, f.e. if you only want to check for missing or invalid keys only.

import { checkTranslations } from "@lingual/i18n-check";

const options = {
  format: "icu",
  checks: ["invalidKeys"],
};

const { invalidKeys } = checkTranslations(source, targets, options);

Calling checkTranslation will return the following shape:

export type CheckResult = Record<string, string[]>;

type Result = {
  missingKeys: CheckResult | undefined;
  invalidKeys: CheckResult | undefined;
};

The result for missingKeys as well as invalidKeys is an object containing the provided locales and their corresponding affected keys as an array

{
  missingKeys:
    {
        "de-de": ["missing_example_key", "some_other_key"],
        "fr-fr": [],
    }
};

i18nCheck.checkMissingTranslations(source, targets)

checkMissingTranslations checks for any missing keys in the target files. All files are compared against the source file.

import { checkMissingTranslations } from "@lingual/i18n-check";

const result = checkMissingTranslations(source, targets);

// {
//  "de-de": ["missing_translation_key", "some_other_missing_translation_key"],
//  "fr-fr": [],
// };

The result is an object containing the provided locales and their corresponding missing keys as an array.

i18nCheck.checkInvalidTranslations(source, targets [, options])

checkInvalidTranslations checks if there are any invalid keys in the target files. All files are compared against the source file.

import { checkInvalidTranslations } from "@lingual/i18n-check";

const options = {
  format: "i18next",
};

const result = checkInvalidTranslations(source, targets, options);

// {
//  "de-de": ["invalid_translation_key", "some_other_invalid_translation_key"],
//  "fr-fr": [],
// };

The result is an object containing the provided locales and their corresponding invalid keys as an array.

Development

If you want to checkout and run the code, you need to run the build command first.

Run yarn build, pnpm run build or npm run build and then depending on the scenario one of the following commands.

Basic icu translation example:

node dist/bin/index.js --locales translations/messageExamples -s en-US

Flatted translation keys example:

node dist/bin/index.js --locales translations/flattenExamples -s en-US

i18next translation example:

node dist/bin/index.js --locales translations/i18NextMessageExamples -s en-US -f i18next

Single file translation example:

node dist/bin/index.js --locales translations/folderExample -s en-US

Multiple files per folder translation example:

node dist/bin/index.js --locales translations/multipleFilesFolderExample/ -s en-US

Multiple folders containing locales translation example:

node dist/bin/index.js --locales translations/folderExample,translations/messageExamples -s en-US

Tests

To run the tests use one of the following commands:

pnpm test

yarn test

npm test

Links

• Introducing i18n-check
• Twitter