エラー： The template root requires exactly one element

複数の要素を入れる場合は

divタグなどで１つに括ってあげる。

<template>
  <p>いいね({{ number }})</p>
  <button @click="increment">+1</button>
</template>

<script>
export default {
   data() {
     return {
       number: 7
     };
   },
   methods: {
     increment(){
       this.number += 1;
     }
   }
};
</script>

Failed to compile.

./src/LikeNumber.vue
Module Error (from ./node_modules/eslint-loader/index.js):

/Users/maedatakuo/projects/udemy-vuejs/src/LikeNumber.vue
  3:3  error  The template root requires exactly one element  vue/valid-template-root

✖ 1 problem (1 error, 0 warnings)

<template>
<div>
  <p>いいね({{ number }})</p>
  <button @click="increment">+1</button>
</div>
</template>

<script>
export default {
   data() {
     return {
       number: 7
     };
   },
   methods: {
     increment(){
       this.number += 1;
     }
   }
};
</script>