No If slider (thanks math) written in JavaScript -> https://dev.to/ranewallin/this-simple-math-hack-lets-you-create-an-image-carousel-without-any-if-statements-5chj

NoIfSlider.js

const imageData = [ 'image1.png', 'img2.png', 'img3.png' ];
const currentImage = 0;

const handleImageChange = (direction) => {
  if (direction == 'forward')
    currentImage = (currentImage + 1) % imageData.length;
  else
    currentImage = (currentImage - 1 + imageData.length) % imageData.length;
}