SOURCE

var arr = [1,2,3,4,5,6,7,8];
let size = 3;
for(let i = 0; i < Math.ceil(arr.length / size); i++) {
    let start = i * size;
    let end = start + size;
    let subArr = arr.slice(start, end);
    console.log(subArr);
}

console.log(0%2);
console.log(1%2);
console.log(2%2);
console.log(3%2);