JS Algorithm – Chunk array

Given an array and chunk size, divide the array into many subarrays where each subarray is of length size.

Examples
chunk([1, 2, 3, 4], 2) –> [[ 1, 2], [3, 4]]
chunk([1, 2, 3, 4, 5], 2) –> [[ 1, 2], [3, 4], [5]]
chunk([1, 2, 3, 4, 5, 6, 7, 8], 3) –> [[ 1, 2, 3], [4, 5, 6], [7, 8]]
chunk([1, 2, 3, 4, 5], 4) –> [[ 1, 2, 3, 4], [5]]
chunk([1, 2, 3, 4, 5], 10) –> [[ 1, 2, 3, 4, 5]]

First solution:

function chunk(array, size) {
  // Declaring new empty array to save the result
  // this chunked array wrap the chunked arrays.
  const chunked = [];

  // To define from where index to which index the
  // main array will be sliced
  let index = 0;

  // Go through every item in the main array
  // 0 to the total of items in the array
  while (index < array.length) {
    // saving the sliced items into the chunked array
    chunked.push(array.slice(index, index + size));

    // Incrementing the index with the size (original)
    index += size;
  }

  return chunked;
}

chunk([1, 2, 3, 4, 5], 2);

Result:

Second solution:

function chunk(array, size) {
  let chunked = [];

  for (let item of array) {

    let lastElement = chunked[chunked.length - 1];

    if (!lastElement || lastElement.length === size) {
      chunked.push([item]);
    } else {
      lastElement.push(item);
    }
  }

  return chunked;
}

chunk([1, 2, 3, 4, 5], 2);

Result:

Third solution:

function chunk(array, size) {
  var results = [];

  while (array.length) {
    results.push(array.splice(0, size));
  }
  return results;
};

chunk([1, 2, 3, 4, 5], 2);

Result:

By Cristina Rojas.