What is the difference between map and filter in JavaScript?

What is the difference between map and filter in JavaScript?

The map method creates a new array by applying a function to each element of the original array, while filter creates a new array with elements that pass a test defined by a function.

Can you give me an example of both?

Sure! For map, if you have an array [1, 2, 3] and you use map to multiply each by 2, you'll get [2, 4, 6]. For filter, if you want to keep only even numbers from [1, 2, 3, 4], you'd use filter and get [2, 4].

When should I use map instead of filter?

Use map when you want to transform each element of an array into a new array. Use filter when you want to select a subset of elements based on a condition.

Are there any performance differences between them?

Yes, performance can vary based on the size of the array and the complexity of the function used. Generally, map and filter have similar performance, but using them together can lead to inefficiencies.