Conditional logic with `when` and `unless`

About 408 wordsAbout 1 min

Overview

The when() and unless() helpers let you conditionally modify a Filterable instance based on a boolean expression. They provide a fluent, chainable alternative to verbose if/else statements. Both methods modify the current instance and return $this, making them ideal for method chaining.

API

public function when(bool $condition, callable $callback): static
public function unless(bool $condition, callable $callback): static

// The callback receives the current instance:
// function (\Kettasoft\Filterable\Filterable $filterable): void

Basic usage

`when()`

Executes the callback only when the condition is true.

use Kettasoft\Filterable\Filterable;

$filter = Filterable::create()
    ->when($isAdmin, function (Filterable $f) {
        $f->setAllowedFields(['email', 'role']);
    })
    ->when($request->boolean('strict'), fn ($f) => $f->strict());

`unless()`

Executes the callback only when the condition is false (inverse of when).

use Kettasoft\Filterable\Filterable;

$filter = Filterable::create()
    ->unless($isAdmin, function (Filterable $f) {
        // Non-admins get a restricted set of fields
        $f->setAllowedFields(['name']);
    })
    ->unless($request->boolean('include_inactive'), function ($f) {
        // Apply additional constraints when a flag is NOT set
        $f->through([
            fn ($builder) => $builder->where('active', true),
        ]);
    });

You can use short arrow functions for compact callbacks:

Filterable::create()->when($flag, fn ($f) => $f->permissive());

Nesting and composition

when() and unless() can be freely nested and combined.

Filterable::create()
    ->when($isAdmin, function ($f) {
        $f->setAllowedFields(['*']);

        $f->unless($isReadonlyMode, function ($f) {
            $f->sorting(fn ($s) => $s->default('created_at', 'desc'));

            $f->when(true, fn ($f) => $f->ignoreEmptyValues());
        });
    })
    ->unless($isGuest, fn ($f) => $f->strict());

Real-world examples

Role-based field access

$filter = Filterable::create()
    ->when($user->isAdmin(), fn ($f) => $f->setAllowedFields(['*']))
    ->unless($user->isAdmin(), fn ($f) => $f->setAllowedFields(['name', 'email']))
    ->apply();

Feature flag toggles

$filter = Filterable::create()
    ->when(config('features.relaxed_filtering'), fn ($f) => $f->permissive())
    ->unless(config('features.allow_all_ops'), fn ($f) => $f->allowedOperators(['=', '!=', 'like']));

Behavior

when($condition, $callback) runs the callback only when $condition === true.
unless($condition, $callback) runs the callback only when $condition === false.
In both cases, the same Filterable instance is returned (chainable, mutating API).
The callback receives the current instance and may call any configuration methods.
If the condition does not match, the callback is not executed.

Tips

Prefer unless($cond) when expressing negative intent (reads naturally).
Combine with through() for custom query tweaks that run only when needed.
Closures are evaluated lazily—only when their conditions match.
Keep callbacks small and focused for readability and testability.

Invokable

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