<template>

    <div>

        <button v-on:click="show = !show">

            Toggle

        </button>

        <transition name="fade">

            <p v-if="show">hello</p>

        </transition>

    </div>

</template>

<script>

    export default {

        data: function() {

            return {

                show: true

            }

        }

    }

</script>

<style>

    .fade-enter-active,

    .fade-leave-active {

        transition: opacity .5s

    }

    .fade-enter,

    .fade-leave-to {

        opacity: 0

    }

</style>