You are using computed incorrectly. You should return the property in the function. See the docs for more information.
Here is your adapted example:
computed: {
currentRouteName() {
return this.$route.name;
}
}
You can then use it like this:
<div>{{ currentRouteName }}</div>
You can also use it directly in the template without using a computed property, like this:
<div>{{ $route.name }}</div>