how to divide an array into subarrays in javascript code example

Example 1: javascript split array into chuncks of

function splitArrayIntoChunksOfLen(arr, len) {
  var chunks = [], i = 0, n = arr.length;
  while (i < n) {
    chunks.push(arr.slice(i, i += len));
  }
  return chunks;
}
var alphabet=['a','b','c','d','e','f'];
var alphabetPairs=splitArrayIntoChunksOfLen(alphabet,2); //split into chunks of two

Example 2: chunk an array

function __chunk(array, size) {
  let chunkArray = [];
  return function _chunk(chunk = array) {
    if (chunk.length < size) {
      return chunkArray.push(chunk) && chunkArray;
    }
    return chunkArray.push(chunk.slice(0, size)) && _chunk(chunk.slice(size));
  };
}