I am working on a project and using swiperJS to create a slider but the breakpoints are not working, your help would be very much appreciated

Question

I am working on a project and using swiperJS to create a slider but the breakpoints are not working, your help would be very much appreciated. Everything else is working with the exception of the breakpoints......

Here is the code...

 <!-- Initialize Swiper -->
     <script>
        var swiper = new Swiper(".slider--container", {
          slidesPerView: 3,
          spaceBetween: 30,
          loop: true,
          centerSlide: 'true',
          fade: 'true',
          grabCursor: 'true',
          pagination: {
            el: ".swiper-pagination",
            clickable: true,
            dynamicBullets: true
          },
          navigation: {
            nextEl: ".swiper-button-next",
            prevEl: ".swiper-button-prev",
          },

          breakpoints: {
            0:{
                slidesPerView: 1,
            },
            520:{
                slidesPerView: 2,
            },
            950:{
                slidesPerView: 3,
            },
          },
        });
      </script>