04 array.map()
let numbers = [1,2,3,4,5]; let newNumbers = numbers.map(n=>n*2); console.log(newNumbers); //2,4,6,8,10 map 메서드로 출력하기 arr.map(callback(currentValue[, index[, array]])[, thisArg]) developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Array/map