Question: how to pass selected value of dropdown in vuejs?
Answer:  Use javascript event: If you don't specify any parameter, the native event object will be passed automatically <select class="sort-filter" v-on:change="sortBy"> ... 
 Using v-model. You can add the v-model directive <select name="test" v-model="sorting" v-on:change="sortBy"> ... 
 Other weird way.