Add Total Word Count to the Publish Box

<?php
// Classic Editor: show word count in the Publish meta box.
add_action( 'post_submitbox_misc_actions', 'scseed_publish_box_word_count' );
if ( ! function_exists( 'scseed_publish_box_word_count' ) ) {
    function scseed_publish_box_word_count() {
        global $post;
        if ( ! $post ) {
            return;
        }
        $count = str_word_count( wp_strip_all_tags( $post->post_content ) );
        printf(
            '<div class="misc-pub-section" style="border-top:1px solid #ddd;padding-top:8px;">%s <strong id="scseed-wc">%s</strong></div>',
            esc_html__( 'Word count:', 'scseed' ),
            number_format_i18n( $count )
        );
    }
}

// Block Editor: subscribe to the data store and refresh the counter live.
add_action( 'enqueue_block_editor_assets', 'scseed_block_editor_word_count' );
if ( ! function_exists( 'scseed_block_editor_word_count' ) ) {
    function scseed_block_editor_word_count() {
        $script = 'wp.data.subscribe( function() {
            var editor = wp.data.select( "core/editor" );
            if ( ! editor ) { return; }
            var content = editor.getEditedPostContent() || "";
            var plain = content.replace( /<[^>]+>/g, " " ).replace( /[ \t\n\r]+/g, " " ).trim();
            var words = plain ? plain.split( " " ).filter( Boolean ).length : 0;
            var el = document.getElementById( "scseed-wc" );
            if ( el ) { el.textContent = words.toLocaleString(); }
        } );';
        wp_add_inline_script( 'wp-edit-post', $script );
    }
}