Improve typescript declarations

[Shinigami92]

Currently the declarations created in #111 are not very helpful.

Maybe you can improve them and pick up the declarations from here:
https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/vuex-i18n/index.d.ts

After that we can remove it from DefinitelyTyped

[vuduongq]

Hi @Shinigami92

Thanks for providing the typescript declarations. I have updated the d.ts of the package.

[Shinigami92]

In which case can this.$t('something') return undefined?

vuex-i18n/dist/vuex-i18n.d.ts

Line 6 in 2c54cea

$t(key: string, options?: any, pluralization?: number): string | undefined;

I thought if the key is missing, 'something' will be returned. I think it is never returning undefined.

I use strict in my projects, and after every $t call, I have to append a ! to tell TypeScript that I don't assume undefined.

Edit: Also looking into your code

vuex-i18n/src/vuex-i18n-plugin.js

Line 98 in 67fc6b5

let defaultValue = '';

The defaultValue is empty string and I think this is a good idea!

[tikiatua]

Version 2 of the plugin is in the works and completely written in typescript (see version 2 branch)