Hi Guys,
I have reviewed @madan's code & jyoti's code too. There were few...

Hi Guys,

I have reviewed @madan's code & jyoti's code too. There were few issues in both, i am working on fixing the issues & will release the D8 port soon.

@jyoti : I was not able to apply your patch, But i have used your code as a reference.

Below are some of the issues that i had to work on.

[1] After enabling the module and placing the block in to region it's working fine. But after clearing cache Ajax is not working.

So for that I removed the ajax callback from controller and added in to Form itself. Based on that few more changes which I did inside ajax callback.

[2] Replacing t() to $this->t().

[3] In result added the .

[4] Removal the whitespaces.

[5] Block was not visible for Anonymous User So made the changes in Block Permission.