Messages and parameters

Interpolation

Write parameters in the form {name}. Each required argument accepts a string, number or boolean; a required value cannot be null or undefined.

{
  "greeting": "Hola {name}",
  "ready": "Listo para traducir",
  "cart": {
    "items": {
      "plural": "total",
      "forms": {
        "=0": "Tu cesta está vacía",
        "one": "{count} elemento en tu cesta",
        "other": "{count} elementos en tu cesta"
      }
    }
  }
}

const { t } = useI18n()
t('greeting', { name: 'Meeko' })
t('ready')
t('cart.items', { total: 3 })

// Expected TypeScript diagnostics:
t('greeting')                        // missing name
t('cart.items', { total: 'three' })  // requires a number
t('unknown')                         // nonexistent key

The same contract between languages

Every language needs the same namespaces, keys and parameters. If one translation uses name and another uses user for the same message, preparing the module fails. Plural categories can vary by language.

Public types

Dynamic keys

A union of keys needs valid arguments for every alternative. Narrow the key with an if when each case has different parameters. If any alternative requires values, the argument cannot be omitted.

Old registries declared as true keep their open contract. The module generates new registries with explicit parameters.