1d-array to 2d-array with reduce

array-reduce.js

let postObject = posts.reverse().reduce((acc, ele) => {
      if(acc.s > 0) {
        return {arr: [ele, ...acc.arr], rows: acc.rows, s: acc.s-1}
      } else {
        return {arr: [ele], rows: [acc.arr, ...acc.rows], s: 2};
      }
    }, {arr: [], rows: [], s: 3});
    let rows = [[...postObject.arr], ...postObject.rows ];