Hook JS into WooCommerce Email function - php

Question

I am trying to add some JS for Trustpilot in my WooCommerce processing order emails (customer-processing-order.php). I am currently trying to just echo it with a function in functions.php like so:
add_action ('woocommerce_email_header', 'add_trustpilot_script', 9999, 3);
function add_trustpilot_script ($headers, $email_id, $order ){
$theSku = '';
foreach ( $order->get_items() as $item_id => $item ) {
$sku = $item->get_sku();
$theSku .= $sku . ',';
}
$tSku = substr($theSku, 0,-1);
echo '<script type="application/json+trustpilot">
{
"recipientName": "'. $order->get_billing_first_name().'",
"recipientEmail": "'. $order->get_billing_email().'",
"referenceId": "'. $order->get_id().'",
"productSkus": ["'.$tSku.'"]
}
</script>';
}
But the above is not working :( any help appreciated.

Answer 1

Your code contains some minor errors
$order is not an argument in the woocommerce_email_header hook
$email->id is used in an if condition, to target the customer_processing_order email
$item->get_sku(); is replaced by $product->get_sku();
So you get:
function action_woocommerce_email_header( $email_heading, $email ) {
// Only for order processing email
if ( $email->id == 'customer_processing_order' ) {
// Get an instance of the WC_Order object
$order = $email->object;
// Is a WC_Order
if ( is_a( $order, 'WC_Order' ) ) {
// Empty string
$theSku = '';
foreach ( $order->get_items() as $item_id => $item ) {
// Get an instance of corresponding the WC_Product object
$product = $item->get_product();
// Get product SKU
$product_sku = $product->get_sku();
$theSku .= $product_sku . ',';
}
$tSku = substr( $theSku, 0, -1 );
echo '<script type="application/json+trustpilot">
{
"recipientName": "' . $order->get_billing_first_name() . '",
"recipientEmail": "' . $order->get_billing_email() . '",
"referenceId": "' . $order->get_id() . '",
"productSkus": ["' . $tSku . '"]
}
</script>';
}
}
}
add_action( 'woocommerce_email_header', 'action_woocommerce_email_header', 10, 2 );
Note: the results can be found in the email source, one email client displays the results visually, the other does not, so it depends on which email client you use