Split Array object into chucks

December 2, 2021

I have this array in JS

initialArray = [A,B,C,C,D,E,F,F,G,K]

I want to split into:

chucks = [[A,B,C], [C,D,E,F], [F,G,K]]

Duplicate items are separators such as ‘C’ or ‘F’

How to do this split in ES6?

>Solution :

Fairly straight forward solution using a single for loop and holding the current chunk in a variable to push to.

const initialArray = ['A', 'A', 'B', 'C', 'C', 'D', 'E', 'F', 'F', 'G', 'K', 'K'];

const chunk_at_duplicate = (arr) => {
  let chunk = [], res = [chunk];

  for (let i = 0; i < arr.length; i++) {
    if (arr[i] === arr[i - 1]) {
      res.push(chunk = []);
    }

    chunk.push(arr[i]);
  }

  return res;
};

console.log(chunk_at_duplicate(initialArray));