判断数组是否包含某元素

<template>
  <div>
    <el-button @click="examination()">测试</el-button>
  </div>
</template>
<script>
  export default {
    name: 'JavaScript',
    data(){
      return{
        arr1:[1, 2, 3, 4, 5, 6, 7, 8],
        arr2:[1, 2],
        arr3:[3, 9]
      }
    },
    methods:{
      includes(arr1, arr2) {
         return arr2.every(val => arr1.includes(val));
      },
      examination(){
        let a = this.includes(this.arr1,this.arr2)
        let b = this.includes(this.arr1,this.arr3)
        console.log(a)  //true
        console.log(b)  //false
      }
    }
  }
</script>