Autofocus in a modal activated via the store - vue.js

Question

I want to find a prettier solution on that problematic :
A click on a main component button set to true the var showUserAddModal in the store
// App.vue
// ...
computed: {
...mapGetters('admin', [ 'showUserAddModal' ])
}
// ...
methods: {
...mapMutations('admin', [ 'setShowUserAddModal' ])
}
// ...
A modal component is displayed :
<div class="modal" :class="{ 'is-active': showUserAddModal }">
I want to give focus into an inpput text localized in a sub-sub-component
CalendarAdminUserAdd.vue > AutoCompletion.vue
// App.vue
// ...
<div class="modal" :class="{ 'is-active': showUserAddModal }">
<div class="modal-background"></div>
<calendar-admin-user-add team-id="9" ref="calendaradminuseradd" />
</div>
// ...
// CalendarAdminUserAdd.vue
<template>
<div class="modal-card">
// ...
<auto-completion width="400px"
max-height="400px"
#input="selectUser($event)"
ref="adsearchcomponent" />
// ...
</template>
// AutoCompletion.vue
<template>
<div class="dropdown is-active">
<div class="dropdown-trigger">
<input type="text" class="input" ref="searchinput"
placeholder="Nom Prénom" v-model="searchFilter"
#keyup="searchUser" />
</div>
// ...
</template>
// ...
The issue is, with the use of the store, that the setShowUserAddModal method is coming from the store (mapMutations) and have, by nature, an asynchrone behaviour. And I can't figure out how I can catch the effective display event of the modal, to execute my focus() on it. For the moment, with a poor setTimeout, it works :
// App.vue
// ...
watch: {
showUserAddModal : function () {
setTimeout( () => {
this.$refs.calendaradminuseradd.$refs.adsearchcomponent.$refs.searchinput.focus()
}, 500)
}
}
// ...
Even with a nextTick() it doesn't work.
I use the framework CSS Bulma for the modal, with no Javascript, so I don't think that Bulma could interfer.
The store :
// store/admin.js
export default {
namespaced: true,
state: {
showUserAddModal: false
},
getters: {
showUserAddModal: state => state.showUserAddModal
},
mutations: {
setShowUserAddModal(state, showUserAddModal) {
state.showUserAddModal = showUserAddModal
}
}
}
Here I am, thank you for reading til here ;) and thanks for your help !