There are a lot of built-in functions in PHP like count or in_array. But how to get their javascript versions. For that Viewi integrates Locutus: locutus.io github.com/locutusjs/locutus
This library contains a big variety of javascript functions that are implemented in a way to repeat their PHP analogs. For the moment of writing this page Locutus is licensed under the MIT licenses. But please make sure it still is before using it in your project.
If there is some missing function that you would like to have in javascript, please request it either on Viewi’s github page or on Locutus’s github page.
By the way, Locutus also has libraries for C, Ruby, Go and Python in case you need it.