Is something like PLV8 exist in Microsoft SQL Server (JavaScript procedural language add-on for Microsoft SQL Server)?
You can utilise the CLR integration in MS SQL Server, and write managed code (C# / VB.Net / possibly other languages) that you will be able to execute from within SQL Server.
Having said that, the fact that such a possibility exists doesn't necessarily imply that it should be used. Very few tasks actually benefit from being implemented in managed code compared to T-SQL, such as (the list is by no means complete):
Before going this way, make sure your team understands performance and security implications related to this approach, as they are many. The aforementioned link gives you a good starting point.