Sending Wrapper object to Apex

public class AccountWrapper
{

@auraenabled
public string Name{get;set;}
@auraenabled
public integer NumberOfEmployees{get;set;}
@AuraEnabled
public List<Contact> Contacts { get; set; }

}

public class AccountService {

@auraenabled
public static void createAccountContact(AccountWrapper wrapper)
{
    system.debug('wrapper:'+wrapper);
    if(wrapper!=null)
    {
        Account act=new Account();
        act.Name=wrapper.Name;
        act.NumberOfEmployees=wrapper.NumberOfEmployees;
        insert act;

        if(wrapper.Contacts!=null)
        {
            for(Contact ct:wrapper.Contacts)
            {
                ct.AccountId=act.id;
            }
            insert wrapper.Contacts;
        }
    }
}

}

import { LightningElement } from 'lwc';
import createAccountContact from '@salesforce/apex/AccountService.createAccountContact';
export default class ApexWrapperCall extends LightningElement {

contacts=[];
error;
handleClick(e)
{
    var contact=
    {
        LastName:'Sahni',
        Email:'[e-mail]',
        Phone:'9871506648'
    };
    this.contacts.push(contact);
    var pass=
    {
        Name:'Dhanik',
        NumberOfEmployees:2,
        Contacts:this.contacts
    };
    createAccountContact({wrapper:pass})
    .then(result => {
        console.log('Data:'+ JSON.stringify(result));
    }) .catch(error => {
        console.log(error);
        this.error = error;
    }); 
}

}

Link:
https://salesforcecodex.com/salesforce/sending-wrapper-object-to-apex-from-lwc/