@murmur 不是哦，比如计算数组中元素出现的次数，弄成对象属性
const list = ["a", "b", "c", "a", "a"];

const countedList = list.reduce(function (acc, cur) {
if (cur in acc) {
acc[cur]++;
} else {
acc[cur] = 1;
}
return acc;
}, {});
console.log(countedList);

// {a: 3, b: 1, c: 1}