When should I use map or forEach in JavaScript?

Can you explain when to use map or forEach in JavaScript?

Sure! Use map when you want to transform an array and create a new one, while forEach is for executing a function on each element without creating a new array.

What are the main differences between map and forEach?

The main difference is that map returns a new array with the results of calling a function on every element, whereas forEach returns undefined and is used for side effects.

Can I use forEach if I need to create a new array?

It's not recommended. While you can push elements to a new array inside forEach, it's less efficient and not the intended use. Stick with map for that.

Are there performance differences between them?

Yes, map can be slightly more performant for creating new arrays since it's optimized for that purpose, while forEach is more about executing side effects.