map

예제

📗 배열안의 객체 값 변경하기

let array = [
  {number : [1,2,3]},{number : [2,3,4]},{number : [4,5,6]}
];

function x(array){
	return array.map(x => {
      const sum = x.number.reduce((a,b) => { return a+b }, 0);
      const average = sum/x.number.length;
      //return x.number = average;
      //이렇게 끝나면 결과 [2,3,5];
      x.number = average;
      return x;
      //이렇게 x 그자체를 돌려주어야함
      //[{number:2},{number:3},{number:5}]
    });
}