What are the differences between spread and concat in JavaScript?

What are the differences between spread and concat in JavaScript?

The spread operator (...) allows you to expand elements of an iterable (like an array) into individual elements, while concat() is a method that merges two or more arrays.

Can you give me an example of how to use both?

Sure! Using spread: const arr1 = [1, 2]; const arr2 = [3, 4]; const combined = [...arr1, ...arr2]; Using concat: const combined = arr1.concat(arr2); Both will result in [1, 2, 3, 4].

Are there any performance differences between them?

Yes, the spread operator can be slightly slower for large arrays due to the way it creates a new array, while concat is generally more efficient for merging.

Which one should I use in my code?

It depends on your needs. Use spread for readability and when you need to expand elements, and concat for straightforward merging.