What are some common mistakes when using JavaScript array methods?

What are some common mistakes when using JavaScript array methods?

Some common mistakes include misunderstanding how methods like map, filter, and reduce work, especially with their return values.

Can you explain the difference between map and forEach?

Sure! map creates a new array with the results of calling a provided function on every element, while forEach executes a provided function once for each array element but does not return a new array.

What happens if I forget to return a value in map?

If you forget to return a value in map, the new array will contain undefined for those elements where no value was returned.

Are there any performance issues with using filter and map together?

Yes, chaining filter and map can lead to performance issues because it creates intermediate arrays. It's often better to use a single reduce for better performance.