What do `map()` and `forEach()` methods return respectively?

The map() and forEach() methods serve different purposes in JavaScript, and their return values reflect their functions accordingly.

The map() method is designed to create a new array by applying a provided function to each element of the original array. The key characteristic of map() is that it returns this new array, containing the results of each function call. This return value is essential for functional programming patterns where transformations of arrays are common.

On the other hand, the forEach() method is used to execute a provided function once for each array element. Its main purpose is to perform side effects for each element without creating a new array. Because its role is to iterate through the elements and execute side effects, forEach() does not return any value; thus, it returns undefined.

This distinction is critical in using these methods effectively in JavaScript. Choosing between them depends on whether you need a transformed array (in which case you would use map()) or just need to perform operations on each item without caring about the result (in which case forEach() is appropriate).