SOURCE

const app = Vue.createApp({
    template: `<van-tabs v-model:active="active">
        <van-tab title="语文" name="a"></van-tab>
        <van-tab v-if="showSecond" title="数学" name="b"></van-tab>
        <van-tab name="c">
        <template #title>历史</template>
        </van-tab>
    </van-tabs>`,
    data() {
        return {
            showSecond: false
        }
    },
    mounted() {
        this.showSecond = true
    }
});
app.use(vant);
app.mount('#app');

<div id="app">
    
</div>