typescript_objectkeys.tsx

type CountryCode = keyof typeof Countries;

const countries: Country[] = (Object.keys(Countries) as Array<CountryCode>).map(
    (c) => {
        const country = Countries[c];
        return {
            code: c,
            name: country.name,
            nativeName: country.native,
            flag: country.emojiU,
        };
    }
);

declare global {
    interface ObjectConstructor {
        typedKeys<T>(o: T) : Array<keyof T>
    }
}
Object.typedKeys = Object.keys as any