Magento 2 - How to remove/unset all categories from a product using plugin?

Question

I am trying to remove/unset all categories from a product using below code. It's working with Magento 2.1 but not with Magento 2.2.

How can we do this?

app/code/Vender/Module/etc/di.xml

<plugin name="Vender-Module-product-model" type="Vender\Module\Plugin\TestPlugin" sortOrder="1" />

app/code/Vender/Module/Plugin/TestPlugin.php

namespace Vender\Module\Plugin;

class TestPlugin    
{ 
    public function beforeSave(\Magento\Catalog\Model\Product $product)   
    {
        $product->setCategoryIds("1");
    }

}

Any help would be appreciated!

Answer 1

If it was working fine with 2.1 and not working on 2.2. I suggest you to using factory class of product class.

public function beforeSave(\Magento\Catalog\Model\ProductFactory $product)
{
  $prod = $product->create()->load(<product id>);
  $prod->setCategoryIds("1");  
 // $prod->save();
  $prod->getResource()->save();      
} 

It is recommended to use factory class.