javaScript基础面试题---找出多维数组最大值

function fnArr(arr) { 
    var newArr = [];

    arr.forEach((item,index) => {
        newArr.push(Math.max(...item))
    })

    return newArr
 }


console.log(fnArr([
    [4,5,1,3],
    [13,27,18,26],
    [32,35,37,39],
    [1000,1001,857,1]
]))