//数组去重
const unique = (arr) => [ ...new Set(arr)]
// 或者遍历比较
// 对象用for(let key in obj)
// 数组用for (let i = 0; i< 10; i++)
const unique1 = (arr) => {
const arr1 = [];
for (let i = 0; i < arr.lenght;i++) {
if (arr1.indexOf(arr[i]) !== -1) {
arr1.push(arr[i])
}
}
}