<b-nav-item-dropdown>
          <template slot="button-content">
          <em>Button</em>
        </template>
        <b-dropdown-item href="#">
<a href="" :click="foo()">Execute foo</a></b-dropdown-item>
        </b-nav-item-dropdown>
<script>
export default {
  methods: {
    foo() {
      console.log("executing methods");
    },
  }
}
</script>