When you are creating the router, you can specify the linkExactActiveClass
as a property to set the class that will be used for the active router link.
const routes = [
{ path: '/foo', component: Foo },
{ path: '/bar', component: Bar }
]
const router = new VueRouter({
routes,
linkActiveClass: "active", // active class for non-exact links.
linkExactActiveClass: "active" // active class for *exact* links.
})
This is documented here.