Discussion on: Array Rotation in JS

[Medet Tleukabiluly ✎]

return arr.slice(d).concat(arr.slice(0, d)) is enough

[Shubham Tiwari]

Thank you i will try this
Can you please explain this code?
I am getting a bit confused with it

[peerreynders]

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]

Better?

Array.prototype.slice() - JavaScript | MDN

The slice() method returns a shallow copy of a portion of an array into a new array object selected from start to end (end not included) where start and end represent the index of items in that array. The original array will not be modified.

developer.mozilla.org

[Shubham Tiwari]

Got it thank you for explaining 😉

[JoelBonetR 🥇]

Also Number.parseInt(arr.length % d) could be useful in case the number is greater than the arr length.

const completeRotations = arr.length / d;

let extraSteps = Number.parseInt(arr.length % d);

With that you can simply do a single complete rotation and keeo going the extra steps instead of failing 😁

[Shubham Tiwari]

Thank you i will try this as well 😉