JS array method foreach and map comparison

Looked up some JS Array methods forEach and map Information , It is simply sorted out for your reference

map Method

const arrMap = [1, 2, 3, 4, 5];
const arrMapModified = arrMap.map(num => num * 2);
console.log(arrMap);
// [1, 2, 3, 4, 5]
console.log(arrMapModified);
// [2, 4, 6, 8, 10]

map Method raw array arrMap Will not change , Allocate storage space and return a new array arrMapModified

forEach Method

const arrayForEach = [1, 2, 3, 4, 5];
const arrayForEachModified = arrayForEach.forEach((item, index) => arrayForEach[index] = item * 2);
console.log(arrayForEach);
// [2, 4, 6, 8, 10]
console.log(arrayForEachModified);
// undefined

forEach Method raw array arrayForEach Will change , Do not return a new array , The value is undefined