[Vuejs]-Vue.js route params

The last ? means this parameter is optional.

The vue-router will not complain if you do not pass this parameter while building the dynamic route.

You can do

this.$router.push({
    name: coursePage,
    params: { contentId: 1 }
})

or

this.$router.push({
    name: coursePage,
    params: { contentId: 1, title: 2 }
})