JSFiddle - React, Tailwind, and code Playground

HTML

<div class="indicator">
  <span></span>
</div>

CSS

.indicator {
  background: #d1d1d1;
  height: 6px;
  width: 100%;
}

.indicator span {
  display: block;
  width: 10%;
  height: 6px;
  background: orange;
}

JavaScript

//Входные значения
let sliderImages = ['url1', 'url2', 'url3'];
let currentSlide = 2;

const indicator = document.querySelector('.indicator > span');
const sectionWidth = 100 / sliderImages.length;

indicator.style.width = `${sectionWidth}%`

//Вызываем каждый раз при изменении текущего слайда
indicator.style.marginLeft = `${sectionWidth * currentSlide}%`