JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr = [1,2,3,4,5,6,7];

function chunk(arr, n) {
  return arr.reduce(function (p, c, i) {
    if (i % n === 0) p.push([]);
    p[p.length - 1].push(c);
    return p;
  }, []);
}

console.log(chunk(arr, 2));