JSFiddle - React, Tailwind, and code Playground

JavaScript

const input = [{
  i: 0,
  abc: true
}, {
  i: 1,
  abc: true
}, {
  i: 2,
  abc: true
}, {
  i: 3,
  abc: true
}, {
  i: 4,
  abc: true
}, {
  i: 5,
  abc: true
}, {
  i: 6,
  abc: true
}, {
  i: 7,
  abc: true
}, {
  i: 8,
  abc: true
}, {
  i: 9,
  abc: true
}, {
  i: 10,
  abc: true
}, {
  i: 11,
  abc: true
}, ]


const result = input.reduce((acc, x, i) => {
  if (i % 3 === 0) {
    acc.push([x])
  } else {
    acc[acc.length-1].push(x)
  }
  return acc;
}, [])

console.log(result)