object value is array split by length code example

Example 1: javascript array split chunk

const chunk = (arr, size) => arr.reduce((acc, e, i) => (i % size ? acc[acc.length - 1].push(e) : acc.push([e]), acc), []);

// Examples
chunk([1, 2, 3, 4, 5, 6, 7, 8], 3);     // [[1, 2, 3], [4, 5, 6], [7, 8]]
chunk([1, 2, 3, 4, 5, 6, 7, 8], 4);     // [[1, 2, 3, 4], [5, 6, 7, 8]]

Example 2: 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