Add code highlighting to WordPress

Add the following code snippet to your functions.php file in your WordPress theme and save it and refresh your page.

add_action( 'wp_enqueue_scripts', 'enqueue_highlightjs_assets' );

function enqueue_highlightjs_assets() {
    // Enable the plugin only for singular posts
    // if ( ! is_singular() ) {
    // 		return;
    // 	}

    // You can update the theme file with default.min.css or any other theme.
	wp_enqueue_style( 'highlightjs-css', '//cdn.jsdelivr.net/gh/highlightjs/cdn-release@latest/build/styles/atom-one-dark.min.css' );

	wp_enqueue_script( 'highlightjs', '//cdn.jsdelivr.net/gh/highlightjs/cdn-release@latest/build/highlight.min.js', 'latest', true);

        wp_add_inline_script( 'highlightjs', 'hljs.highlightAll();' );
}