How to identify (get id) which tab is selected?

Questions
1

In f7 v2 vue it was easy to identify the tab for ex.

on: {
        pageBeforeRemove() {
            console.log('page before remove')
        },
        tabShow: function(tabEl) {
            const targettab = tabEl.target.id;
        }
}

but how to do it in v3. The same code is not working
how can I use

app.on('tabShow'...

to get the selected tab id?

2 
app.on('tabShow', (tabEl) => {
  const targettab = tabEl.id;
})
3

Or

<f7-page @tab:show.native="onTabShow">...

methods: {
  onTabShow(event) {
    const targettab = event.target.id;
  }