What are the best practices for using filter and map in JavaScript?

What are the best practices for using filter and map in JavaScript?

When using filter and map, ensure you understand their purposes: filter is for selecting elements, while map transforms them.

Can you give me an example of using both filter and map together?

Sure! You can first filter an array to get only even numbers, then map to square those numbers. For example:

const numbers = [1, 2, 3, 4, 5]; const result = numbers.filter(n => n % 2 === 0).map(n => n * n); This will give you [4, 16].

Are there any performance considerations I should keep in mind?

Yes, chaining filter and map can lead to performance issues with large datasets. Consider using a single loop for better efficiency.

What about using them with asynchronous operations?

Both filter and map are synchronous. If you need to handle asynchronous operations, consider using Promise.all with map to handle promises.