Basic Data Structures: Copy an Array with the Spread Operator

Tell us what’s happening:

I have figured out a solution and found out where the mistake (syntax) lies. But I can’t figure out why the brackets are needed here. I’d like an explanation to understand the difference between.

Crucial part of my code that doesn’t work :

newArr = [...newArr,...arr];

But it is accepted like this :

newArr = [...newArr,[...arr]];

So … is a nested array. the first example puts both arrs in one giant array. The second one nests one array in the other.

So first one makes it like [1,2,3,1,2,3,1,2,3] whereas second one makes it like [[1,2,3],[1,2,3],[1,2,3]] ?

More like: [1,2,[1,2,3]]

When you do these challenges I find it helps to keep you console log open so you can really see the out put.

Oh I was having problems with console log I thought it would print it on the website but got it now, I have to open the browsers console to see the output. I’ve even tried using but unable to make it work, it gave runtime error and etc. but from now on I know what to do, thank you very much :smile:

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