Given a country ISO I can know the country name using Intl.DisplayNames API with:

const countryName = new Intl.DisplayNames([lang], { type: 'region' }).of(countryISO)
console.log(countryName) // France

However, I want to go one step further, and put the preposition in front of the country:

And depending on the country, it may be one or the other... But I don't know how this formula works... Is there any JavaScript API similar to DisplayNames that allows it?

NL:

• FR: aux Pays-Bas
• DE: in die Niederlande
• IT: nei Paesi Bassi

FR:

• FR: en France
• DE: nach Frankreich
• IT: in Francia

GB:

• FR: au Royaume-uni
• DE: ins Vereinigte Königreich
• IT: nel Regno Unito

etc.

Thanks!