给 Relation 添加 getMorphAlias 函数，通过 model 类名获取 relation 映射值

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Laravel discussions

https://github.com/laravel/framework/discussions/42215

Background

Some times, we need to find the morphed alias by model class.

hope to use Relation::getMorphAlias(\App\Models\Xxx::class) get it.

code

\Illuminate\Database\Eloquent\Relations\Relation::macro('getMorphedAlias', function ($value) {
    $morphMap = \Illuminate\Database\Eloquent\Relations\Relation::morphMap();

    $flipMorphed = array_flip($morphMap);

    $alias = $flipMorphed[$value] ?? null;

    return $alias;
});

Example

$id = 1;
$class = \App\Models\Organization::class;
$classAlias = Relation::getMorphedAlias($class);

ImageCover::create([
    'coverable_id' => $id,
    'coverable_type' => $classAlias,
]);

AppServiceProvider.php

    public function register()
    {
       \Illuminate\Database\Eloquent\Relations\Relation::macro('getMorphAlias', function ($value) {
            if (is_object($value)) {
                $value = get_class($value);
            }
            
            $morphMap = \Illuminate\Database\Eloquent\Relations\Relation::morphMap();

            $flipMorphed = array_flip($morphMap);

            $alias = $flipMorphed[$value] ?? throw new \RuntimeException("Please add class $value to \Illuminate\Database\Eloquent\Relations\Relation::enforceMorphMap");

            return $alias;
        });

        // ImageCover
        \Illuminate\Database\Eloquent\Relations\Relation::enforceMorphMap([
            \App\Models\ImageCover::CONVERABLE_ORGANIZATION => \App\Models\Organization::class,
        ]);
    }