SkyVerge - PHP Engineer - How would you improve this code? Please do not fork this Gist.

php-engineer-improve-code.php

<?php
/**
 * This code retrieves course data from an external API and displays it in the user's
 * My Account area. A merchant has noticed that there's a delay when loading the page.
 * 
 * 1) What changes would you suggest to reduce or remove that delay?
 * I've refactored it to retrieve the data from the API using AJAX, so that this does not block the page.
 *
 * 2) Is there any other code changes that you would make?
 * I'd also make the AJAX call secure (nonce) and move the JS and HTML to separate files
 * (to separate presentation from logic and to make it easier to read).
 */

/**
 * Creates a new instance of this class.
 * If there is already a construct, add these lines instead of creating this function (obviously).
 */
public function __construct() {
	// Add AJAX actions.
	add_action( 'wp_ajax_get_courses_table', [ $this, 'get_courses_table' ] );
	add_action( 'wp_ajax_get_course_sso_link', [ $this, 'get_course_sso_link' ] );
	// Add custom JavaScript.
	add_action( 'wp_footer', [ $this, 'enqueue_scripts' ] );
}

/**
 * Get the API user ID from the current user metadata.
 */
protected funcion get_api_user_id() {
	return get_user_meta( get_current_user_id(), '_external_api_user_id', true );
}

/**
 * Retrieves courses from the external API and returns an HTML table.
 */
public function get_courses_table() {
	// Get the API user ID from the user metadata.
	$api_user_id = $this->get_api_user_id();
	// Retrieve the courses from the external API.
	$courses  = $this->get_api()->get_courses_assigned_to_user( $api_user_id );
	// Echo the HTML.
	?>
	<table id="courses-table">
		<thead><tr>
			<th><?php echo __( 'Course Code', 'text-domain' ); ?></th>
			<th><?php echo __( 'Course Title', 'text-domain' ); ?></th>
			<th><?php echo __( 'Completion', 'text-domain' ); ?></th>
			<th><?php echo __( 'Date Completed', 'text-domain' ); ?></th>
		</tr></thead>
		<tbody>
		<?php
		foreach( $courses as $course ) :
			?><tr>
			<td><?php echo __( $course['Code'] ); ?></td>
			<td><?php echo __( $course['Name'] ); ?></td>
			<td><?php echo __( $course['PercentageComplete'] ); ?> &#37;</td>
			<td><?php echo __( $course['DateCompleted'] ); ?></td>
			</tr>
		<?php endforeach;
		?>
		</tbody>
	</table>
	<?php 
	die();
}
				   
/**
 * Retrieves a course's SSO link from the external API and returns an HTML link.
 */
public function get_course_sso_link() {
	// Get the API user ID from the user metadata.
	$api_user_id = $this->get_api_user_id();
	// Get the active course from the sent data (used for style purposes).
	$active_course = $_POST['active_course'];
	// Retrieve the SSO link from the external API.
	$sso_link = $this->get_api()->get_sso_link( $api_user_id );
	// Echo the HTML.
	?>
	<p id="course-login"><a href="<?php echo $sso_link ?>" target="_blank" class="button <?php echo $active_course ?>"><?php echo __( 'Course Login', 'text-domain' ); ?></a></p>
	<?php
	die();
}
				   
/**
 * Add custom JavaScript to call AJAX functions.
 */
public function enqueue_scripts() {
	?>
	<script type="text/javascript">
		// Get courses table and update the HTML.
		jQuery.ajax({
		    url: '<?php echo admin_url( 'admin-ajax.php' ); ?>'
		    type: 'post',
		    data: {
			action: 'get_courses_table'
		    },
		    success: function( response ) {
			jQuery('#courses-table').replaceWith(response);
		    }
		});
		// Get active course link and update the HTML.
		jQuery.ajax({
		    url: '<?php echo admin_url( 'admin-ajax.php' ); ?>'
		    type: 'post',
		    data: {
			action: 'get_course_sso_link',
			active_course: '<?php echo $_GET['active_course']; ?>'
		    },
		    success: function( response ) {
			jQuery('#course-login').replaceWith(response);
		    }
		});
	</script>
	<?php
}				   

public function add_my_courses_section() {

	// Get the API user ID from the user metadata.
	$api_user_id = $this->get_api_user_id();
	if ( ! $api_user_id ) {
		return;
	}

	// Print empty table.
	?>
	<h2 style="margin-top: 40px;"><?php echo __( 'My Courses', 'text-domain' ); ?></h2>
	<table id="courses-table">
		<thead><tr>
			<th><?php echo __( 'Course Code', 'text-domain' ); ?></th>
			<th><?php echo __( 'Course Title', 'text-domain' ); ?></th>
			<th><?php echo __( 'Completion', 'text-domain' ); ?></th>
			<th><?php echo __( 'Date Completed', 'text-domain' ); ?></th>
		</tr></thead>
		<tbody><tr>
			<td colspan="4">Loading...</td>
		</tr></tbody>
	</table>
	<p id="course-login">Loading...</p>
	<?php
}