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

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

When using map, filter, and reduce, it's important to keep your functions pure, avoid side effects, and ensure readability.

Can you give me an example of using these methods together?

Sure! You can use map to transform an array, filter to remove unwanted items, and reduce to aggregate results. For example:

const numbers = [1, 2, 3, 4, 5];
const result = numbers
  .map(num => num * 2) // [2, 4, 6, 8, 10]
  .filter(num => num > 5) // [6, 8, 10]
  .reduce((acc, num) => acc + num, 0); // 24

What should I avoid when using these methods?

Avoid using them for side effects, like modifying external variables. Also, don't use them for complex logic that can reduce readability.

Are there performance considerations I should keep in mind?

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