请问一下怎么获取到setInterval的回调函数的返回值

Question

比如如何获取定时器中的sum， 让sum作为Sum_Solution的返回值

function Sum_Solution(n)
{

// write code here
let temp = 0;
let sum = 0;
var timer = setInterval(function () {
    sum = sum + temp;
    temp++;
    (temp === n + 1) && (clearInterval(timer))
    callback(sum)
},110)

}

Answer 1

function a(func) {
        let num = 0;
        return () => {
            setInterval(function () {
                num++;
                func.call(this, num)
            }, 100)
        }
    }

    a(num => {
        console.log(num)
    })();