Nova Polymorphic Field

Description

A Laravel Nova field that allows you to create a collection of polymorphic resources.

Depending on the polymorphic type you select:

1. Different fields will be populated on the form/detail page of your resource.
2. Records will be automatically created/updated in the corresponding tables.

Demo

Installation

The package can be installed through Composer.

composer require michielkempen/nova-polymorphic-field

Usage

1. Add a morphs field to the migration of your base model.
2. Add the MichielKempen\NovaPolymorphicField\HasPolymorphicFields trait to your Nova Resource.
3. Add the MichielKempen\NovaPolymorphicField\PolymorphicField to your Nova Resource fields method.
4. Specify the different polymorphic types by calling the type($name, $modelClass) method on the PolymorphicField.
   • The $name parameter is a readable name you assign to your polymorphic type.
   • The $modelClass parameter is the class of the polymorphic model.

Example

Migrations:

Schema::create('news_posts', function (Blueprint $table) {
    $table->increments('id');
    $table->string('title');
    $table->morphs('type'); // !!
    $table->timestamps();
});

Schema::create('videos', function (Blueprint $table) {
    $table->increments('id');
    $table->string('url');
});

Schema::create('articles', function (Blueprint $table) {
    $table->increments('id');
    $table->string('image');
    $table->text('text');
});

Resource:

class NewsPost extends Resource
{
    use HasPolymorphicFields;

    public function fields(Request $request)
    {
        return [
            
            Text::make('Title'),

            PolymorphicField::make('Type')
                ->type('Video', \App\Video::class, [

                    Text::make('Url'),

                ])
                ->type('Article', \App\Article::class, [

                    Image::make('Image'),

                    Textarea::make('Text'),

                ]),

        ];
    }
}

You can optionally hide the type selection when updating a resource. This can be useful if you don't want the user to be able to change the Type of a polymorphic relationship once it has been created.

class NewsPost extends Resource
{
    use HasPolymorphicFields;

    public function fields(Request $request)
    {
        return [
            ...
            PolymorphicField::make('Type')
                ->type('Video', \App\Video::class, [
                    Text::make('Url'),
                ])
                ->type('Article', \App\Article::class, [
                    Image::make('Image'),
                    Textarea::make('Text'),
                ])
                ->hideTypeWhenUpdating(),
            ...
        ];

morphMap

By default, the fully qualified class name of the related model will be stored as type field in the base model. However, you may wish to decouple your database from your application's internal structure. In that case, you may define a relationship "morph map" to instruct Eloquent to use a custom name for each model instead of the class name:

use Illuminate\Database\Eloquent\Relations\Relation;

Relation::morphMap([
    'article' => \App\Article::class,
    'video' => \App\Video::class,
]);

You may register the morphMap in the boot function of your AppServiceProvider.

License

The MIT License (MIT). Please see License File for more information.