function sliceArray(array, size) {
var result = [];
for (var x = 0; x < Math.ceil(array.length / size); x++) {
var start = x * size;
var end = start + size;
result.push(array.slice(start, end));
}
return result;
}
let list = [1,2,3,4,5,6,7,8]
console.log(sliceArray(list,3)); //[[1,2,3],[4,5,6],[7,8]]