Format billing phone number on Checkout form submission in Woocommerce

Question

I am trying for format the provided phone number to "920001234567" format just at the moment when customer click on submit button. I want the phone number to get stored in database with this format. Here is the code I am trying to use. What's wrong in it?

add_action( 'woocommerce_checkout_update_order_meta', 
  'formatPhoneOnComplete', 10, 2 );
  function formatPhoneOnComplete($order_id) {
  $order = wc_get_order($order_id);
  $order_data = $order->get_data();
  $phone = $order_data['billing']['phone'];
  $phone = trim($phone);
  $phone = str_replace([' ','-','_'],'',$phone);
    if(empty($phone)) {
        return NULL;
    }
    $phone = ltrim(ltrim($phone, '0'),'+');
    if(strlen($phone) <= 11) {
        $phone = '92' . ltrim($phone,0);
    }
    return $phone;
}

Answer 1

Try the following as your code is not really saving anything in database as returning the formatted value, is not the right way in an action hook.

The woocommerce_checkout_create_order action hook is a really better alternative to woocommerce_checkout_update_order_meta hook…

I have reuse your formatting code in the following hooked function:

add_action( 'woocommerce_checkout_create_order', 'additional_hidden_checkout_field_save', 20, 2 );
function additional_hidden_checkout_field_save( $order, $data ) {
    if( ! isset($data['billing_phone']) ) return;

    if( ! empty($data['billing_phone']) ){
        $phone = str_replace([' ','-','_'],['','',''], $data['billing_phone']);
        $phone = ltrim(ltrim($phone, '0'),'+');
        $formatted_phone = strlen($phone) <= 11 ? '92' . ltrim($phone, 0) : $phone;
        // Set the formatted billing phone for the order
        $order->set_billing_phone( $formatted_phone );
    }
}

Code goes in function.php file of your active child theme (or active theme). tested and work.