Vue i18n - "Property '$t' does not exist on type 'VueConstructor'" error. How can I fix it?

Question

JavaScript

Using vue i18n in a typescript project.
How to use it correctly in .ts files?
This approach

// for i18n
import  Vue  from 'vue'
declare module 'vue/types/vue' {
  interface VueConstructor  {
    $t: any
  }
}
declare module 'vue/types/options' {
  interface ComponentOptions<V extends Vue> {
    t?: any
  }
}

(()=>{
  const test = Vue.$t('auth.title');
  console.log( test )
})()

Gives ts error

Property '$t' does not exist on type 'VueConstructor<Vue>"

How can this be fixed?

Answer 1

$t must be on an instance of the Vue class, not a static property of it.