... is the spread operator. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax

thanks, i gas i dumb i dont understand anything(

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set

This is almost what I tried to do but I didn't know how to properly do the sort() part. I am still trying to understand this (a - b). Good to see a working example.

Really clever and understandable

Thanks for your explanation.

array || [] evaluates to array when array is a truthy value and otherwise evaluates to an empty array.

So, array = array || [] will set array equal to an empty array if it does not already refer to an object.

Not sure what array = array || [] means and how it returns 0