While reading through closed PR #55537, I realized one could use a custom JSON encoder for Eloquent's built-in casters, by providing a custom callable implementation using:

// assuming MyJsonEncoder is an invokable class,
// this method accepts any callable
Illuminate\Database\Eloquent\Casts\Json::encodeUsing(new MyJsonEncoder());

Then I remembered that, I recently migrated a project from Laravel 8, to Laravel 12, which uses a custom encoder, in a very similar fashion.

But as on Laravel 8, this class wasn't available (it was introduced on Laravel 10, by PR #46552), I ended up duplicating some of the built-in casters to make use of this encoder.

While reviewing the code to simplify it using this approach, I noticed my custom encoder accepts the $flags from the caster, which the built-in encoder does not.

This PR:

• Updates the Illuminate\Database\Eloquent\Casts\Json::encode() method to pass the $flags argument down to a user provided encoder.

Note: the symmetric Json::decode() static method, already passes the $associative argument down to a user provided decoder.