Removing-Actions-and-Filters.php

To remove a callback function from a hook, you need to call remove_action() or remove_filter(), depending whether the callback function was added as an Action or a Filter.

The parameters passed to remove_action() / remove_filter() must be identical to the parameters passed to add_action() / add_filter() that registered it, or the removal won’t work.

#Example

Lets say we want to improve the performance of a large theme by removing unnecessary functionality.

Let’s analyze the theme’s code by looking into functions.php

function wporg_setup_slider() {
	// ...
}
add_action( 'template_redirect', 'wporg_setup_slider', 9 );


The wporg_setup_slider function is adding a slider that we don’t need, which probably loads a huge CSS file followed by a JavaScript initialization file which uses a custom written library the size of 1MB. We can can get rid of that.

Since we want to hook into WordPress after the wporg_setup_slider callback function was registered (functions.php executed) our best chance would be the after_setup_theme hook.

function wporg_disable_slider() {
	// Make sure all parameters match the add_action() call exactly.
	remove_action( 'template_redirect', 'wporg_setup_slider', 9 );
}
// Make sure we call remove_action() after add_action() has been called.
add_action( 'after_setup_theme', 'wporg_disable_slider' );


h2 Removing All Callbacks
You can also remove all of the callback functions associated with a hook by using remove_all_actions() / remove_all_filters().

h2 Determining the Current Hook
Sometimes you want to run an Action or a Filter on multiple hooks, but behave differently based on which one is currently calling it.

You can use the current_action() / current_filter() to determine the current Action / Filter.


function wporg_modify_content( $content ) {
	switch ( current_filter() ) {
		case 'the_content':
			// Do something.
			break;
		case 'the_excerpt':
			// Do something.
			break;
	}
	return $content;
}

add_filter( 'the_content', 'wporg_modify_content' );
add_filter( 'the_excerpt', 'wporg_modify_content' );

h2 Checking How Many Times a Hook Has Run

function wporg_custom() {
   // If save_post has been run more than once, skip the rest of the code.
   if ( did_action( 'save_post' ) !== 1 ) {
      return;
   }
   // ...
}
add_action( 'save_post', 'wporg_custom' );


h2 officeal link : https://developer.wordpress.org/plugins/hooks/advanced-topics/