upsell-enqueue

<?php
/**
 * Display upgrade notice on customizer page
 */
function prefix_upsell_notice() {

	// Enqueue the script
	wp_enqueue_script(
		'prefix-customizer-upsell',
		get_template_directory_uri() . '/js/upsell.js',
		array(), '1.0.0',
		true
	);

	// Localize the script
	wp_localize_script(
		'prefix-customizer-upsell',
		'prefixL10n',
		array(
			'prefixURL'	=> esc_url( 'https://upsell.com' ),
			'prefixLabel'	=> __( 'Theme Upsell Link', 'textdomain' ),
		)
	);

}
add_action( 'customize_controls_enqueue_scripts', 'prefix_upsell_notice' );
?>