JSFiddle - React, Tailwind, and code Playground
JavaScript
function rotateLeft(d, arr) {
const endToBegin = arr.slice(d);
const beginToEnd = arr.slice(0,d);
return endToBegin.concat(beginToEnd);
}
const array = [1,2,3,4,5,6]
const rotation = 2
console.log(rotateLeft(rotation,array)) // [3, 4, 5, 6, 1, 2]