has_action vs did_action in WordPress

has_action

Basically, we use the has_action() function to check if any action( callback ) has been registered for a hook.

The WordPress has_action() function expects two parameters when called. The first parameter is $hook_name, and the second parameter $callback is a callback function.

The first parameter, $hook_name, is required. This means you must need to pass the $hook_name with this function. The second parameter $callback is optional.

If the $callback parameter is not passed, it returns a boolean for whether the hook has anything registered. When checking a specific function passing by the second parameter $callback, the priority of that hook is returned or false if the function is not attached.

Let’s see an example:
I developed plugins like Product Catalog Mode For WooCommerce, Woo Parent Category Selector, Remove Add to Cart Button for WooCommerce etc.

In the Remove Add to Cart Button for WooCommerce plugin, I called a callback function with the plugins_loaded action hook to check if WooCommerce is active before running my plugin function.

add_action( 'plugins_loaded', 'ratcw_remove_add_to_cart_button_install', 12 );
function ratcw_remove_add_to_cart_button_install(){
	if ( !function_exists( 'WC' ) ) {
		add_action( 'admin_notices', 'ratcw_remove_add_to_cart_button_admin_notice' );
	} else {
		ratcw_run_remove_add_to_cart_button_woocommerce();
	}
}

}

So now, if we call the has_action() function like

var_dump(has_action('plugins_loaded','ratcw_remove_add_to_cart_button_install'));

It will return the priority of this callback function.

Here we can see the output is 12, which is the priority of that callback function.

did_action

Retrieves the number of times an action has been fired during the current request. Let’s describe with an example:

If you take a look at the WooCommerce cart template file, you can see an action hook point is created there. Here is the code :

do_action( 'woocommerce_after_cart_item_name', $cart_item, $cart_item_key );

It calls all callback functions attached to that hook(woocommerce_after_cart_item_name).

So now, if I add a callback function to woocommerce_after_cart_item_name using the add_action() function and add some product to the cart and visit the cart page, there we will see how many times woocommerce_after_cart_item_name is called using did_action('woocommerce_after_cart_item_name'); function.

If you have 3 products on your cart, you will see woocommerce_after_cart_item_name called 3 times.

Please check the screenshot below for more details: