Return types in TypeScript declaration files are too narrow

[DanielSWolf]

According to index.d.ts, the function getAlpha2Code always returns a string. According to the unit tests, it returns a string on success, undefined otherwise.

The type definition should be changed to read

export function getAlpha2Code(name: string, lang: string): string | undefined;

I suspect that the same is true for most of the functions.

[e110c0]

MR would be welcome for this

[DanielSWolf]

I've created a PR.

[e110c0]

Thank you. PR merged and will be in the next release.