Quick Edit Plugin

quick-edit.php

<?php
/**
 * Plugin Name: NS inline edit
 * Plugin URL: https://www.nuno-sarmento.com
 * Description: Add excerpt to WordPress Posts Quick Edit
 * Requires at least: 5.0
 * Tested up to: 5.4
 * Version: 0.1
 * Plugin Author: Nuno Sarmento
 * Author URI: https://www.nuno-sarmento.com
 */

// Exit if accessed directly.
defined( 'ABSPATH' ) || exit;

add_action( 'quick_edit_custom_box', function( $column_name, $post_type ){

	if ( 'portfolio' === $post_type && 'post_excerpt' === $column_name ){ ?>

		<fieldset class="inline-edit-col-left inline-edit-custom" style="clear: left;">
			<div class="inline-edit-col inline-edit-<?php echo $column_name ?>">
				<label><?php _e( 'Excerpt', 'quick-edit-pro' ); ?>
					<textarea name="<?php echo $column_name; ?>"></textarea>
				</label>
			</div>
		</fieldset>

	<?php }

}, 10, 2 );

add_filter( 'manage_posts_columns', function( $columns ) {

	return array_merge( $columns,
              array( 'post_excerpt' => __( 'Excerpt' ) ) );

}, 10, 2 );

add_action( 'manage_posts_custom_column' , function( $column, $post_id ){

	if ( 'post_excerpt' === $column ){
		$post = get_post( $post_id );
		echo $post->post_excerpt;
	}


}, 10, 2 );


add_action( 'save_post', 'ns_update_post' );
function ns_update_post( $post_id ) {
	$slug = 'portfolio';

	if ( $slug !== $_POST['post_type'] ) {
		return;
	}
	
	// verify if this is an auto save routine. If it is our form has not been submitted,
	// so we dont want to do anything
	if ( defined('DOING_AUTOSAVE') && DOING_AUTOSAVE )
		return $post_id;


	if ( !current_user_can( 'edit_post', $post_id ) ) {
		return;
	}

	// checkboxes are submitted if checked, absent if not
	if ( isset( $_REQUEST['post_excerpt'] ) ) {
		
		remove_action( 'save_post', 'ns_update_post' );
		$args = array(				
			'ID'              => $post_id,				
			'post_excerpt' => esc_html( $_REQUEST['post_excerpt'] )		
		);			

		wp_update_post( $args );			
		// Now hook the action			
		add_action( 'save_post', 'ns_update_post' );
	}
	return;
}


add_action( 'admin_print_footer_scripts', function(){ ?>
	<script type="text/javascript">

		(function($) {

			// we create a copy of the WP inline edit post function
			var $wp_inline_edit = inlineEditPost.edit;

			// and then we overwrite the function with our own code
			inlineEditPost.edit = function( id ) {

				// "call" the original WP edit function
				// we don't want to leave WordPress hanging
				$wp_inline_edit.apply( this, arguments );

				// now we take care of our business

				// get the post ID
				var $post_id = 0;
				if ( typeof( id ) == 'object' ) {
					$post_id = parseInt( this.getId( id ) );
				}

				if ( $post_id > 0 ) {
					// define the edit row
					var $edit_row = $( '#edit-' + $post_id );
					var $post_row = $( '#post-' + $post_id );

					// get the data
					var $post_excerpt = $( '.column-post_excerpt', $post_row ).text();

					// populate the data
					$( ':input[name="post_excerpt"]', $edit_row ).val( $post_excerpt );
				}
			};

		})(jQuery);

	</script>

<?php

}, 1000 );