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

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

Spread parameters allow an iterable to expand in places where zero or more arguments are expected, while rest parameters collect multiple elements into an array. In terms of performance, spread can be slightly slower due to the creation of new arrays, while rest parameters are generally more efficient for function arguments.

Can you give me an example of each?

Sure! For spread parameters, you might use it like this: const arr = [1, 2, 3]; console.log(...arr); This spreads the array elements. For rest parameters, you can define a function like this: function sum(...numbers) { return numbers.reduce((a, b) => a + b, 0); } This collects all arguments into an array.

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

Yes, if you need to pass an array as individual arguments, use spread. If you want to handle an unknown number of arguments in a function, use rest parameters.

What about their impact on memory usage?

Spread parameters can lead to higher memory usage since they create new arrays, while rest parameters are more memory-efficient as they directly collect arguments.