Question - How to make router param changes as reactive? 
          
        
        Answer - 
        
When you navigate from one URL to other(mapped with a single component) using routes with params then the same component instance will be reused. Even though it is more efficient than destroying the old instance and then creating a new one, the lifecycle hooks of the component will not be called.
This problem can be solved using either of the below approaches,
Watch the $route object:
const User = {
  template: '
User {{ $route.params.name }} 
',
  watch: {
    '$route' (to, from) {
      // react to route changes...
    }
  }
}
Use beforeRouteUpdate navigation guard: This is only available since 2.2 version.
const User = {
  template: '
User {{ $route.params.name }} 
',
  beforeRouteUpdate (to, from, next) {
    // react to route changes and then call next()
  }
}
Note that the beforeRouteEnter guard does NOT have access to this. Instead you can pass a callback to next to access the vm instance.