Add when() method to Fields

[fschirinzi]

I think it would be a nice feature to have the when($condition, $callback) method on the Field class.

Currently, when I conditionally want to set field settings, I have to create the field outside of the array and reference to it. Example NOW:

class MyResource extends Resource
{
    public function fields(NovaRequest $request)
    {
        $belongsToUserField =  BelongsTo::make('User')->hideWhenCreating()->readonly();
        if ($request->viaResource()) {
            $belongsToUserField->show();
        }

        return [ 
            $belongsToUserField,
        ]
    }
}

Example with when

class MyResource extends Resource
{
    public function fields(NovaRequest $request)
    {
        return [ 
            BelongsTo::make('User')
                ->hideWhenCreating()
                ->readonly()
                ->when($request->viaResource(), fn($field) => $field->show()),
        ]
    }
}

The second example is much nicer and cleaner. 🤗

[crynobone]

Field already implements Macroable, you should be able to add the macro for your purpose.