First time using swiper ,I followed the documentation, I added the html part in my code I initialize it in JS, I initialize pagination but it is not showing on my page. This is my code:

var Swiper = require('swiper');
  $(document).ready(() => { 
    var swiper = new Swiper('.swiper-container', {   
      pagination: { 
       el: '.swiper-pagination', 
     } 
    });
  }); 

  //HTML 
 <div class="swiper-container"> 
   <div class="swiper-wrapper">
     <div class="swiper-slide"> Slide 1 </div>
     <div class="swiper-slide"> Slide 2 </div>
     <div class="swiper-slide"> Slide 3 </div>
     <div class="swiper-slide"> Slide 4 </div>
  </div> 
  <div class="swiper-pagination"> </div>
 </div>

can someone explain me what am I doing wrong I get the pagination element height and width 0px,