Update custom post type title

Question

I want to update the post meta of a custom post type when a user updates the custom post type's title in the admin backend. Something like the pseudo code below;

if ((get_the_title() !== $val_in_title_field) && (Publish == true)) 
{
    update_post_meta( $id, 'custom_field', '' );
}

I am not clear on how to check what is passed from the title field when a user clicks publish and all how to check if a uer has clicked publish.

Answer 1

Try this out,

add_filter( 'wp_insert_post_data' , 'modify_post_title' , '50', 2 );

function modify_post_title( $data , $postarr )
{
  if($data['post_type'] == '{custom post type}') {
      if($data['post_title'] == $postarr['post_title']){
            update_post_meta( $data["ID"], 'custom_field', '' );
      }
  }
  return $data;
}

Reference: https://wordpress.org/support/topic/modifying-title-before-saving-custom-post