chunk

function chunk(array, size) { 
    let len = array.length;
    let lineNum = len % size === 0 ? len / size : Math.floor( (len / size) + 1 );
    let res = [];
    for (let i = 0; i < lineNum; i++) {
        let temp = array.slice(i*size, i*size+size);
        res.push(temp);
    }
    return res 
}