Debug hook sequence in WordPress.

debug-hook-sequence.php

<?php
/**
 * Debug WordPress hook sequence.
 *
 * > How it works?
 * 	Add query parameter `debug` in URL e.g. https://<mysite>/?debug
 * 	It'll show the list of Actions in sequence.
 * 
 * @todo Change `prefix_` with your own prefix.
 * 
 * @since 1.0.0
 */
if( ! function_exists( 'prefix_hook_sequence' ) ) {
	function prefix_hook_sequence() {
		?>
		<style type="text/css">
			.toggle-hooks {
			    position: fixed;
			    right: 40px;
			    bottom: 40px;
			    background: #FFC107;
			    color: #000;
			    font-size: 14px;
			    padding: 10px 20px;
			    font-weight: 600;
			    cursor: pointer;
			    z-index: 999999;
			}
			.hooks-sequence-wrap {
			    position: fixed;
			    left: 0;
			    right: 0;
			    top: 0;
			    bottom: 0;
			    z-index: 99999;
			    overflow: hidden;
			    background: #fff;
			}

			.hooks-sequence {
			    overflow-y: auto;
			    max-height: 100vh;
			    max-width: 700px;
			    margin: 0 auto;
			    padding: 30px 0;
			}

			body.hooks-hidden {
			    overflow: hidden;
			}

			.hooks-sequence li {
			    line-height: 1.5;
			}

			.hooks-sequence ul {
			    margin-left: 30px;
			    list-style-type: circle;
			}

			.hooks-sequence h3 {
			    margin: 0 0 30px 0;
			}
			.action-count {
			    background: #f1f1f1;
			    font-size: 10px;
			    font-weight: bold;
			    padding: 1px 4px;
			    border-radius: 3px;
			}
		</style>
		<div class="toggle-hooks show-hooks">Show Actions</div>
		<div class="hooks-sequence-wrap" style="display: none;">
			<div class="hooks-sequence">
				<h3>Currently Executed Actions</h3>
				<ul>
					<?php
				    foreach( $GLOBALS['wp_actions'] as $action => $count ) {
						echo '<li>'.$action .' <span class="action-count">' .$count. '</span></li>';
				    }
					?>
				</ul>
			</div>
		</div>
		<script type="text/javascript">
			(function($){
				$(function(){
					$('.toggle-hooks').click(function() {
						if( $( this).hasClass( 'show-hooks' ) ) {
							$('body').addClass('hooks-hidden');
							$( this).removeClass( 'show-hooks' ).text('Hide Actions');
							$('.hooks-sequence-wrap').show();
						} else {
							$('.hooks-sequence-wrap').hide();
							$('body').removeClass('hooks-hidden');
							$( this).addClass( 'show-hooks' ).text('Show Actions');
						}
					})
				});
			})(jQuery);
		</script>
		<?php
	}

	// Add hook.
	add_action( 'shutdown', 'prefix_hook_sequence' );
}