Demo: return the value of wc_get_product_id_by_sku() by ajax calling in wp plugin

wc_data_getter.php

<?php
/*
Plugin Name: WC Data Getter
Plugin URI: 
Description: For demonstration
Version: 1.0
Author: audi
*/

add_action( 'wp_head', 'my_ajax_form' );
function my_ajax_form() {
	$ajax_url = admin_url( 'admin-ajax.php' );
	?>
	<script>
	const $ = jQuery.noConflict();
	$.ajax({
		async: true,
		type: 'POST',
		url: '<?php echo $ajax_url;?>',
		data: {
			action: 'my_ajax_func',
			sku: '9m88'
		},
		dataType: 'JSON',
		success: function(res) {
			alert(res.data.msg);
			console.log(res.data);
		},
		error:function (xhr, ajaxOptions, thrownError){
			alert(ajaxOptions+':'+thrownError);
		}
	});	
	</script>
	<?php
}

add_action( 'wp_ajax_my_ajax_func', 'my_ajax_func' );
add_action( 'wp_ajax_nopriv_my_ajax_func', 'my_ajax_func' );
function my_ajax_func() {
	global $wpdb;
	$sku = isset($_POST['sku']) ? sanitize_text_field( $_POST['sku'] ) : '';
	if (empty($sku)) {
		wp_send_json_error(array('code' => 500, 'pid' => '', 'msg' => 'sku is empty.'));
	}
	$pid = wc_get_product_id_by_sku( $sku );
	if (!$pid) {
		wp_send_json_error(array('code' => 500, 'pid' => '', 'msg' => 'product not found.'));
	}

	wp_send_json_success(array('code' => 200, 'pid' => $pid, 'msg'=> 'success'));
}