If you have setup your translations, but later on need to translate a new feature then these tips might be useful:
You can fail your CI build by setting the "report missing translations" feature to
error (default is
warning) via the
--i18nMissingTranslation=error flag or by adding the
i18nMissingTranslation option to all language-specific configurations in
To automatically add and merge new string into your existing ones you can leverage Xliffmerge, which comes with it's own Angular CLI scaffolding.