What are the differences between spread and rest syntax in JavaScript?

What are the differences between spread and rest syntax in JavaScript?

Spread syntax allows an iterable to expand in places where zero or more arguments are expected, while rest syntax collects multiple elements into an array.

Can you give me examples of both?

Sure! For spread, you can use it like this: const arr = [1, 2, 3]; const newArr = [...arr, 4, 5]; For rest, it looks like this: function myFunction(...args) { return args; }.

Are there any performance differences between them?

Generally, the performance difference is negligible for most use cases, but spread can be slightly slower due to creating new arrays.

When should I use one over the other?

Use spread when you want to expand elements, and use rest when you want to gather multiple arguments into a single array.