Translation catalog check

This tool checks the project's messages and their translations: strings written straight into the code, keys missing from a locale, placeholders that differ between locales. How the project stores its messages decides which checks apply, and that is found in the project.

Finding it

Look for the message catalogs (a locales/ directory, .po and .pot files, JSON or YAML catalogs per language), for the i18n library in the dependencies, and in the task file or CI for an extract or check step.

Using it

• Extract and compare: the messages extracted from the code (formatjs extract, i18next-parser, xgettext) are compared with each locale's catalog, so missing and unused keys show.
• Check the placeholders: msgfmt --check for gettext catalogs; for ICU messages, each locale's text parsed with the library the app uses.
• Find hard-coded strings with a lint rule, such as no-literal-string from eslint-plugin-i18next.
• Build a pseudo-locale: accented, lengthened text shows strings that overflow their space or were never translated.

Examples: FormatJS (JavaScript), i18next tooling (JavaScript), gettext's msgfmt --check, Android Lint's MissingTranslation check (Android).