When should I use forEach vs map in JavaScript?

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

Sure! Use forEach when you want to execute a function on each element without returning a new array. Use map when you want to transform each element and create a new array.

What happens if I use map but don't return anything?

If you use map without returning a value, the new array will be filled with 'undefined' for each element.

Can I use forEach to create a new array?

No, forEach does not return a new array. It simply executes a function on each element. Use map for that purpose.

Are there performance differences between the two?

Yes, map can be slightly slower than forEach because it creates a new array. However, the difference is usually negligible for small datasets.