adjust array to center

adjustToCenter.js

console.clear();

const uno = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'];
let activeIndex = 1;
const visibleElements = 5;
const centerElement = parseInt(visibleElements / 2, 0);

const dos = uno.map((item, index) => {
  let adjustedIndex = index + 2 + activeIndex;
  let level = 3;
  
  adjustedIndex = adjustedIndex % uno.length;
  
  if (adjustedIndex < visibleElements) {
    level = centerElement - adjustedIndex;
  }

  return {newIndex: adjustedIndex % uno.length, item, level};
})

console.log(dos);