When should I use array.concat vs the spread operator?

What's the difference between using array.concat and the spread operator in JavaScript?

Both methods are used to combine arrays, but they have different syntax and use cases. array.concat creates a new array by merging two or more arrays, while the spread operator (...) allows you to expand an array into individual elements.

When should I choose one over the other?

Use array.concat when you want to combine arrays without modifying the original arrays. Use the spread operator for a more concise syntax, especially when you need to insert elements into an array.

Are there any performance differences between the two?

Yes, in general, the spread operator can be slightly faster for smaller arrays, but for larger arrays, the performance difference is negligible. It's best to choose based on readability and maintainability.

Can you give me an example of both?

Sure! For array.concat, you would do something like let newArray = array1.concat(array2);. For the spread operator, it would be let newArray = [...array1, ...array2];. Both will give you a new array containing elements from both.