How to enqueue a style using wp_enqueue_scripts()?

Question

I'm having difficult to load the path correctly in an 'enqueue' function.

What I am trying to achieve is to load a specific CSS stylesheet on a specific page...

The below works by adding the path to the markup on the correct template - but - the path is wrong...

 add_action('wp_enqueue_scripts','homepage');
  function homepage(){
    if ( is_page_template('page-home.php') ) {
      wp_enqueue_style('home-css', array(), '1.0.0', true );
      get_template_directory_uri() . '/css/flags.min.css',
    }
  }

The reason is because (I believe) the path is not set correctly to find the appropriate css folder...

The php is therefore missing this line:

get_template_directory_uri() . '/css/flags.min.css',

My question is - how do I add this line that locates the theme css folder? I tried the below but it did NOT work...

 add_action('wp_enqueue_scripts','homepage');
  function homepage(){
   if ( is_page_template('page-home.php') ) {
      wp_enqueue_style('home-css', array(), '1.0.0', true );
      get_template_directory_uri() . '/css/flags.min.css',
    }
   }

Answer 1

The second parameter of wp_enqueue_style() is an optional path.You are passing an empty array, which will enqueue nothing.

get_template_directory_uri() retrieves the current theme's root URI, which you can use in wp_enqueue_style():

 add_action('wp_enqueue_scripts','homepage');
  function homepage(){
   if ( is_page_template('page-home.php') ) {
      wp_enqueue_style('home-css', get_template_directory_uri() . '/css/flags.min.css', '1.0.0', true );
    }
   }

I mentioned "Optional", since there is also another way to use wp_enqueue_style. In this method, you can first use wp_register_style, and then enqueue it:

wp_register_style( 'home-css', get_template_directory_uri() . '/css/flags.min.css' );
wp_enqueue_style('home-css');

The same works for wp_enqueue_script().

Based on using parent theme or child, you might also want to take a look into get_stylesheet_directory_uri() too.