js 将长度不确定的数组分割成n个一组的数组

代码实现：

const transSliceImg = (imgs, num) => {
    let newImgs = []
    return imgs.reduce(function(pre,item,index,imgs){
        var begin =index*num;
        var end =begin+num;
        var res = imgs.slice(begin,end); 
        if(res.length != 0){
            newImgs[index] = res;
        }
        return newImgs;
    },[]);
}