1d array to 2d array

JavaScript

var arr = [1,2,3,4,5,6,7,8,9,3];

var newArr = [];
while(arr.length) 
    newArr.push(arr.splice(0,3));

console.log("newArr: %o", newArr);


var m = [1, 2, 3, 4, 5, 6, 7, 8, 9,1,3];
var n = [];
var i = 0;
for (l = m.length; ;i += 3) {
    n.push(m.slice(i, i + 3));
    if ( (i + 3) > l )
        break;
}

console.log("n: %o", n);