Array.nth.of.js

const
  arrPrototype = Object.getPrototypeOf([]);

const {
  from: arrayFrom,
  isArray,

} = Array;

function createListOfChunkLists(arr, chunkCount) {
  return arr.reduce((list, item, idx) => {
    if (idx % chunkCount === 0) {

      list.push([ item ]);
    } else {
      // list.at(-1).push(item);
      list[list.length - 1].push(item);
    }
    return list;
  }, []);
}

function getNthItemOfChunkCount(arr, nthIndex, chunkCount) {
  if (!isArray(arr)) {
    throw (new TypeError(
      'The "nth().of()" chain needs to operate a list like structure.'
    ));
  }
  if (Number.isNaN(chunkCount)) {
    throw (new TypeError(
      'The chunk count needs to be an integer value.'
    ));
  }
  if (chunkCount > arr.length) {
    throw (new RangeError(
      "The chunk count value has to be lower than or equal to the operated list structure's length."
    ));
  }
  if (
       Number.isNaN(nthIndex)
    || (nthIndex < 0)
  //|| ((nthIndex < 0) && ((nthIndex + chunkCount) <= 0))
    || ((nthIndex >= 0) && ((nthIndex + 1) >= chunkCount))
  ) {
    throw (new RangeError(
      "The nth index needs to be an integer value which has to be reasonable within the chunk count's context."
    ));
  }
  return createListOfChunkLists(arr, chunkCount)
    .map((chunkList, idx) => ({

      item: chunkList[nthIndex],
      idx: ((idx * chunkCount) + nthIndex),
    }));
}

class NthItemOfChunkCount {
  #arr;
  #idx;
  constructor(arr, idx) {
    this.#arr = arr;
    this.#idx = idx;
  }
  of(int) {
    return getNthItemOfChunkCount(this.#arr, this.#idx, parseInt(int, 10));
  }
}

function nthItemOfChunkCount(int) {
  const arr = (isArray(this) && this) || arrayFrom(this ?? []);
  const idx = parseInt(int, 10) - 1;

  return (new NthItemOfChunkCount(arr, idx));
}

Object.defineProperty(arrPrototype, 'nth', {
  configurable: true,
  writable: true,
  value: nthItemOfChunkCount
});
Object.defineProperty(arrPrototype.nth, 'toString', {
  value: () => 'function nth() { [custom code] }'
});

Object.defineProperty(NthItemOfChunkCount.prototype.of, 'toString', {
  value: () => 'function of() { [custom code] }'
});

// export default Array;

/**
 *  Get every nth element of an array
 *  [https://stackoverflow.com/questions/68588326/get-every-nth-element-of-an-array/68593956#68593956]
 */

/* const cells = [
  'a1', 'a2', 'a3', 'a4', 'a5', 'a6', 'a7', 'a8', 'a9',
  'b1', 'b2', 'b3', 'b4', 'b5', 'b6', 'b7', 'b8', 'b9',
  'c1', 'c2', 'c3', 'c4', 'c5', 'c6', 'c7', 'c8', 'c9',
];

console.log(
  "cells.nth(7).of(9).map(({ item }) => item) ...",
  cells.nth(7).of(9).map(({ item }) => item)
);

console.log(
  "cells.nth(7).of(9) ...",
  cells.nth(7).of(9)
);

console.log(
  "cells.nth(3).of(6) ...",
  cells.nth(3).of(6)
);
console.log(
  "cells.nth(2).of(3) ...",
  cells.nth(2).of(3)
);

console.log(
  "cells.nth ...",
  cells.nth
);
console.log(
  "cells.nth(2) ...",
  cells.nth(2)
);
console.log(
  "cells.nth(2).of ...",
  cells.nth(2).of
); */