js如何合把二维数组中单个数组 对应求和 合并成一维数组

Question

let array =[[0,1,2,3,4,5],[9,8,7,6,5,4]];
array数组长度不确定

想要结果为 arr = [9,9,9,9,9,9]
对应 0+ 9 1+8 2+7 .........

Answer 1

let result = arr.reduce(function(r, a){
  if(!a instanceof Array)return r;
  for(let i=0; i<a.length; i++)
    r[i]=r[i]?r[i]+a[i]:a[i]
  return r;
},[])
console.log(result)

Answer 2

let array =[[0,1,2,3,4,5],[9,8,7,6,5,4]];
let arr=array.reduce((t,n)=>n.map((e,i)=>(t[i]?t[i]:0)+e),[]);
console.log(arr);