[9.x] Add Conditionable Trait to Illuminate\Support\Carbon

[ralphjsmit]

Today I had a situation where I needed to set the week-number of a Carbon date, but only when a user selected a filter. Otherwise the Carbon instance should default to the current time.

I think that many developers as well have had the situation where they wanted to conditionably apply a method to a Carbon object. At least, I've had this feeling multiple times previously.

I could've done this with an if-condition, but I really missed the elegance of using the ->when() method from the Conditionable, so this looked like the perfect situation for adding the Conditionable trait.

Simple example

// Could be `null` or `[$year, $week]`
$filter = /** */

// Old:
$carbon = $filter ? Carbon::now()->setIsoDate(...$filter) : Carbon::now();

// New:
$carbon = Carbon::now()->when($filter, fn(Carbon $carbon) => $carbon->setIsoDate(...$filter));

I hope this will be useful to many developers!

[DarkGhostHunter]

I was just gonna make this PR...

[driesvints]

I actually think the old way is so much cleaner here 😅

[ralphjsmit]

I actually think the old way is so much cleaner here 😅

😅 There might be better examples, where it's more of an improvement. This is just rather simplified, as everyone knows how the Conditionable works :)

How about this?

$carbon = Carbon::now()
    ->when($filter, fn (Carbon $carbon) => $carbon->setIsoDate(...$filter))
    ->startOfWeek();

// Versus
$carbon = $filter
    ? Carbon::now()->setIsoDate(...$filter)->startOfWeek()
    : Carbon::now()->startOfWeek();

// Or ...
$carbon = Carbon::now()
    ->when($filter)->setIsoDate(...$filter)
    ->startOfWeek();

It's just that I prefer closures over proxies, because it's annoying to lose autocompletion.