feat: add is valid and revoke methods

[NansPellicari]

Hi! For my projects I had to add some features on your component (and thanks for it btw, it is really helpful to me). If you think it is usefull to you I'm glad to share!

[NansPellicari]

Oh sorry! I mess something in the build... I'm on it

[NansPellicari]

Ok the problem was due to a missing polyfill for Object.assign() on the test env.
'Cause of that, mount() function of vue-test-utils package didn't works.

Still a problem occures which break some test codes I try to write :
Probably due to a version compatibilty (I'm sorry but I am not sure, I spend hours on it but I am mostly a beginner on JS env, maybe you have a clue?), the mock creates by mount() does not listen events triggered during the component mounted.

So if you don't mind, for now I quote the tests I'm talking about (I can remove them for the sake of clarity), and if you are interested in, I can create a new pull request trying to update all dependencies and the test env? Do you mind if I changed with the recommended test-runner jest?

[apertureless]

Hi @NansPellicari

thanks for the PR.
Well, yeah the dev dependencies could be quite outdated.

I can look the coming days into the error.

If you want, feel free to swap karma out for jest. I am also mostly using jest now, but back then when the package was created jest wasn't a thing xD

[apertureless]

Hey @NansPellicari !
Can you please update your PR ? I've merged the new jest test env. But now we have some merge conflicts.

[NansPellicari]

Sure, of course ! I'm on It

[NansPellicari]

Done!