Why are there advantages to using both spread operator and destructuring assignment in function parameters?

Question

I keep encountering this syntax, but I'm having trouble understanding what exactly it's doing:

export class SomeClass extends SomeParent {
    constructor(...[configuration]) {
        // Only reference the "configuration" line of code
    }
}

After trying it in Node REPL, I found that there is no difference between the following two ways of writing:

function foo(...[bar]) { console.log(bar); console.log(arguments) }

...and...

function foo(bar) { console.log(bar); console.log(arguments) }

...So what does it do?

Answer 1

It does seem pointless. You need to ask the author of the code what their intentions are in this regard, and they should at least leave a comment.

However, there is actually a slight difference: the remaining parameters do not count towards the function's number of parameters. Therefore, (function(bar){}).length is 1 and (function(...[bar]){}).length is 0.