Magento2 - How to use _getAdditionalConfig() from \Magento\ConfigurableProduct\Block\Product\View\Type\Configurable

Question

In class \Magento\ConfigurableProduct\Block\Product\View\Type\Configurable there is the function bellow.

/**
 * Returns additional values for js config, con be overridden by descendants
 *
 * @return array
 */
protected function _getAdditionalConfig()
{
    return [];
}

How one could "rewrite" (use plugin) it since it is protected. I wanted to add additional data in this function because it is used in "getJsonConfig" function.

I guess if I'd want to make a plugin I would need to use getJsonConfig function because it is public. Which comes back to my question. Should _getAdditionalConfig() be used by end users or it's just for Magento core use ?

Edit I could use a preference for this block class.

Edit 2 Adding a preference for this block class doesn't seem to work

Edit 3 Made a plugin on \Magento\ConfigurableProduct\Block\Product\View\Type\Configurable. Function used is getJsonConfig.

Answer 1

If you do a preference, you will extend the class and can then rewrite _getAdditionalConfig(). A protected function is available to the class extending the initial class.

See my answer on my own question for a problem where I wanted to add an extra image in the JsonConfig object.

For a Plugin solution, you will indeed need to attack directly on getJsonConfig (a public function) and :

1. json_decode the result
2. array_merge with whatever you want to add
3. json_encode the merged array

I guess that is what you did and told in your Edit 3