Typescript type for values provided to a message

[einarlove]

Is your feature request related to a problem? Please describe.

Given this example:

import { createTranslator } from "next-intl";

const messages = {
  basic: "Hello {name}!",
};

const t = createTranslator({ locale: "en", messages });

t("basic", { name: "world" }) // -> Hello world!
t("basic", { whatever: "world" }) // basic

It gives no error. I would want the values TranslationValues to be typed so that I can't pass anything, undefined or nothing at all.
The ICU message syntax does not allow optional values—as in render something else if no value—, so the translation function should not accept empty values.

Describe the solution you'd like

IntlMessages should know which values are included in the translated string and require them. Unsure of the complexity if it accept dates and the like, but a string | number should be good enough.

Describe alternatives you've considered

I want typescript error for the developer to catch the mistake, and the build to fail. So I've seen no solution for this.

[amannn]

Yep, I agree this would be helpful. This is a duplicate of #410.