What are the performance differences between spread and rest operators in JavaScript?

What are the performance differences between spread and rest operators in JavaScript?

The spread operator (...) is used to expand elements of an iterable, while the rest operator (...) collects multiple elements into an array. Performance-wise, the spread operator can be faster for small arrays, but the rest operator is more efficient for handling variable arguments in functions.

Can you give me an example of each operator?

Sure! For the spread operator: const arr1 = [1, 2, 3]; const arr2 = [...arr1, 4, 5]; This creates a new array. For the rest operator: function sum(...numbers) { return numbers.reduce((acc, num) => acc + num, 0); } This function takes any number of arguments.

Are there any scenarios where one is preferred over the other?

Yes, use the spread operator when you need to expand elements, like merging arrays. Use the rest operator when you want to handle an unknown number of arguments in a function.

What about memory usage? Is there a difference?

Generally, the spread operator can lead to higher memory usage since it creates a new array, while the rest operator simply collects arguments without creating a new array until needed.