Discussion on: PHP 8 features I wish also existed in JavaScript

[Bob]

We're discussing named parameters and the performance hit they would be on JavaScript's runtime.

And TypeScript does a whole lot more than type checking nowadays.

[Conan]

I must chime-in with a report from experience.

Some years ago I worked on a fairly large (~700k lines) JavaScript codebase that implemented a 200-line helper that permitted the following:

function get () {
  var opts = defaults(arguments, {
    byId: null,
    theseItems: '*',
  });
  return [opts.byId, opts.theseItems];
}

get();             // [null, '*']
get(2, 'cats');    // [2, 'cats']
get({ byId: 1 });  // [1, '*']

It was used extensively, including in time-critical places such as during render operations. While there was a performance hit that could be measured with dev-tools, it was nothing compared to the usual day-to-day bottlenecks that were encountered.

The point is to say that sure, worry about performance, but perhaps rest/spread/destructuring isn't the first place you need to look these days.