yeah if you have only one argument to pass then no need for the paranthesis if you have more then one then you need to put paranthesis around argument ( pardon my english )

And mine! ;)

Hi, generally it's a good practice to put 'break' but in some scenario without it might be tricky: For example => when you put bad login, you need to log again and after 3 attempt you will be blocked or whatever and now betweem case 1 and case 3 you can put some info but no need to break it. Maybe it's not a top example but always xd.

See if this can help you: Troubleshooting Your Solution.

When there is only one parameter, the parentheses may be ommited. Similarly, when there is only one expression and this expression is returned, the curly brackets and return keyword may be ommited.

The arrow function does not require parenthese; for example in .map(x=>x...) the parenthese is not brought by the arrow function, but by the map method. You can define a function like this :

const squareNumber=x=>x*x

There is no need of parentheses