How to assign class active to nav-link?

Question

Bootstrap

There is a navbar on bootstrap 4. It has several nav-item elements. I would like to know how you can assign the active attribute to the nav-item element, but not by clicking on it, but depending on the value of a certain variable. That is, for example, if the variable a = 0, then make one element active, if a = 1, then another.

Answer 1

Alternatively add a class using jquery
$("id элемента").addClass("active");