localint

A CLI that catches placeholder mismatches in your i18n locale files before they ship.

When a translator renames {name} to {nom}, your app compiles fine and your tests pass. But at runtime the variable is undefined and users see "Bonjour, !". localint finds these before they reach production.

The problem

// en.json
{ "greeting": "Hello, {name}!" }

// fr.json
{ "greeting": "Bonjour, {nom}!" }

Installation

npm install -g localint

Or run without installing:

npx localint --source locales/en.json --target "locales/*.json"

Usage

localint --source <file> --target <glob> [options]

Options:
  -s, --source <file>      Source locale file (e.g. locales/en.json)
  -t, --target <pattern>   Glob pattern for target locales (e.g. "locales/*.json")
  -r, --reporter <type>    Output format: text (default) or json
      --strict             Also fail on missing keys
  -V, --version            Show version
  -h, --help               Show help

Examples

# Check all locales against English
localint --source locales/en.json --target "locales/*.json"

# Also flag missing keys
localint --source locales/en.json --target "locales/*.json" --strict

# JSON output for tooling
localint --source locales/en.json --target "locales/*.json" --reporter json

Sample output

✗ fr — 1 mismatch(es)
  RENAMED  greeting
           source: Hello, {name}!
           target: Bonjour, {nom}!
           detail: {name} -> {nom}

2 placeholder mismatch(es), 0 missing key(s).

Exits with code 1 on any issues, so it works as a CI check out of the box.

Supported formats

| Format | Example | Used by | |--------|---------|---------| | {name} | Hello, {name}! | vue-i18n, basic JSON | | {{name}} | Hello, {{name}}! | i18next, Handlebars | | %(name)s | Hello, %(name)s! | Python-style printf | | %1$s | Hello, %1$s! | Positional printf | | %s, %d | Hello, %s! | Anonymous printf | | :name | Hello, :name! | Legacy formats |

GitHub Action

- name: Check translations
  uses: moakk/[email protected]
  with:
    source: locales/en.json
    target: "locales/*.json"

Library usage

import { compareLocales, loadLocaleFile } from "localint";

const source = loadLocaleFile("locales/en.json");
const target = loadLocaleFile("locales/fr.json");
const result = compareLocales(source, target);

console.log(result.mismatches);

License

MIT