JS map과 forEach 차이

 

• Use map when you need a new array with modified elements.
• Use forEach when you only need to perform an action on each element without creating a new array.

const numbers = [1, 2, 3];
const doubledNumbers = numbers.map(number => number * 2);
console.log(numbers); // Output: [1, 2, 3] (original array remains unchanged)
console.log(doubledNumbers); // Output: [2, 4, 6]

 

const numbers = [1, 2, 3];
numbers.forEach(number => console.log(number * 10)); // Logs 10, 20, 30
console.log(numbers); // Output: [1, 2, 3] (original array might be unchanged, depending on the callback)