@youneed/logger-plugin-i18n

Translate log messages through an @youneed/i18n translator. Log against stable message keys instead of hard-coded English, and let the plugin render them — interpolating from the record's meta — before serialization.

import { createLogger, format } from "@youneed/logger";
import { createI18n } from "@youneed/i18n";
import { i18nPlugin } from "@youneed/logger-plugin-i18n";

const i18n = createI18n({
  resources: { en: { "server.started": "Listening on :{port}" } },
  locale: "en",
});

const log = createLogger({ format: format.combine(format.timestamp(), format.json()) });
log.use(i18nPlugin(i18n));

log.info("server.started", { port: 3000 }); // → message: "Listening on :3000"

A message that isn't a known key passes through verbatim, so plain-string logs and keyed logs can coexist. The plugin follows the translator's active locale, so switching with i18n.setLocale("de") re-localizes every subsequent line.

It's exposed two ways: i18nFormat(i18n, opts) (a Format, compose it yourself) and i18nPlugin(i18n, opts) (prepends that format via logger.useFormat).

| option | default | meaning | | --- | --- | --- | | paramsKey | — | meta field holding interpolation params; otherwise the whole record feeds interpolation | | localeKey | — | stamp the resolved locale onto the record under this key | | force | false | translate even unknown keys (the translator's missing handler decides the output) |