js怎么判断数组是否包含另一个数组

let a = [1, 2, 3, 4, 5, 6, 7, 8];
let b = [1, 2];
let c = [3, 9];

function includes(arr1, arr2) {
  return arr2.every(val => arr1.includes(val));
}

console.log(includes(a, b));  //true
console.log(includes(a, c));  //false