How to make the root element permanently open in v-treeview?

Question

Vue.js

There is this tree:

<v-treeview
            v-model="selection"
            :search="search"
            :active.sync="active"
            :open="otkrytie"
            dense selectable activatable hoverable            
            :items="treeitems"
            item-disabled="locked"
            color="warning"
            selection-type="independent"
            selected-color="red" />

It has only one top-level element:


I'm not sure what I should put in the otkrytie: [] array so that the top-level element is always open?

Answer 1

data: () => ({
  opened: [],
  ...
}),
watch: {
  opened: {
    immediate: true,
    handler(val) {
      const id = this.treeitems[0].id;
      if (!val.includes(id)) {
        val.push(id);
      }
    }
  },
  ...
},

:open.sync="opened"