Changing the product regular_price for WC REST API v2 output

functions.php

<?php 

// the code below goes in your functions.php file

function my_custom_prepare_shop_order_object($response, $order, $request) {
  if( is_pos() ) {
    $data = $response->get_data();
    $data['regular_price'] = get_post_meta( $data['id'], 'wholesale_customer_wholesale_price', true );
    $response->set_data($data);
  }
  return $response;
}

add_filter( 'woocommerce_rest_prepare_product_object', 'my_custom_prepare_product_object', 20, 3 );
add_filter( 'woocommerce_rest_prepare_product_variation_object', 'my_custom_prepare_product_object', 20, 3 );

The code above had some problems, so I tried to troubleshoot and came up with this...it's not giving an error, but no products display in the POS.

<?php
function my_custom_prepare_product_object($response, $product, $request) {
  if( is_pos() ) {
    $data = $response->get_data();
    $data['price'] = get_post_meta( $data['id'], 'wholesale_customer_wholesale_price', true );
    $response->set_data($data);
  }
  return $response;
}

add_filter( 'woocommerce_rest_prepare_product_object', array( $this, 'my_custom_prepare_product_object' ), 20, 3 );
add_filter( 'woocommerce_rest_prepare_product_variation_object', array( $this, 'my_custom_prepare_product_object' ), 20, 3 );

?>

Sorry, my mistake, I copied the add_filter lines from my plugin code ... it should be a slightly different format for the functions.php file. I've just corrected the code.

Cool. Does there need to be the word "function" in front of line 5?

yes, just updated