Thanks @mboeni I later added text-align: left so it works for lengthy label
<q-tabs v-model="shownTab" vertical no-caps>
<q-tab
v-for="(dataRow, index) in data"
:key="index"
:name="'tab-'+index"
style="justify-content:initial; text-align: left"
>{{dataRow.label}}</q-tab>
</q-tabs>