What is the difference between map and forEach in JavaScript?

What is the difference between map and forEach in JavaScript?

The main difference is that map creates a new array with the results of calling a function on every element, while forEach executes a provided function once for each array element but does not return a new array.

Can you give me an example of how to use both?

Sure! Here's an example:

Using map:

const numbers = [1, 2, 3];
const doubled = numbers.map(num => num * 2);
console.log(doubled); // [2, 4, 6]

Using forEach:

const numbers = [1, 2, 3];
numbers.forEach(num => console.log(num * 2)); // Logs 2, 4, 6

When should I use map instead of forEach?

Use map when you need to transform data and create a new array. Use forEach when you just want to perform an action for each element without needing a new array.

Are there any performance differences between them?

Generally, map can be slightly slower than forEach because it creates a new array. However, the difference is usually negligible unless you're working with very large datasets.