What are the best practices for using array methods in JavaScript?

What are the best practices for using array methods in JavaScript?

When using array methods in JavaScript, it's important to consider readability, performance, and immutability. For example, prefer using map, filter, and reduce for functional programming styles, and avoid mutating the original array.

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

Sure! You can use filter to select specific items and then map to transform them. For instance:

const numbers = [1, 2, 3, 4, 5];
const result = numbers.filter(num => num > 2).map(num => num * 2);
console.log(result); // Output: [6, 8, 10]

What about performance? Are there any methods that are slower?

Yes, methods like splice and shift can be slower because they modify the original array and may require re-indexing. It's often better to use non-mutating methods when performance is a concern.

How can I ensure immutability when working with arrays?

To ensure immutability, you can use methods like concat, slice, or the spread operator to create new arrays instead of modifying the existing ones. This helps prevent side effects in your code.