pullAtIndex

Mutates the original array to filter out the values at the specified indexes.

Use Array.prototype.filter() and Array.prototype.includes() to pull out the values that are not needed. Use Array.prototype.length = 0 to mutate the passed in an array by resetting it's length to zero and Array.prototype.push() to re-populate it with only the pulled values. Use Array.prototype.push() to keep track of pulled values

const pullAtIndex = (arr, pullArr) => {
  let removed = [];
  let pulled = arr
    .map((v, i) => (pullArr.includes(i) ? removed.push(v) : v))
    .filter((v, i) => !pullArr.includes(i));
  arr.length = 0;
  pulled.forEach((v) => arr.push(v));
  return removed;
};

let myArray = ["a", "b", "c", "d"];
let pulled = pullAtIndex(myArray, [1, 3]); // myArray = [ 'a', 'c' ] , pulled = [ 'b', 'd' ]