problem 11 on project euler

euler11.js

var grid = [[8,2,22,97,38,15,0,40,0,75,4,5,7,78,52,12,50,77,91,8],[49,49,99,40,17,81,18,57,60,87,17,40,98,43,69,48,4,56,62,0],
	[81,49,31,73,55,79,14,29,93,71,40,67,53,88,30,3,49,13,36,65],[52,70,95,23,4,60,11,42,69,24,68,56,1,32,56,71,37,2,36,91],
	[22,31,16,71,51,67,63,89,41,92,36,54,22,40,40,28,66,33,13,80],[24,47,32,60,99,3,45,2,44,75,33,53,78,36,84,20,35,17,12,50],
	[32,98,81,28,64,23,67,10,26,38,40,67,59,54,70,66,18,38,64,70],[67,26,20,68,2,62,12,20,95,63,94,39,63,8,40,91,66,49,94,21],
	[24,55,58,5,66,73,99,26,97,17,78,78,96,83,14,88,34,89,63,72],[21,36,23,9,75,0,76,44,20,45,35,14,0,61,33,97,34,31,33,95],
	[78,17,53,28,22,75,31,67,15,94,3,80,4,62,16,14,9,53,56,92],[16,39,5,42,96,35,31,47,55,58,88,24,0,17,54,24,36,29,85,57],
	[86,56,0,48,35,71,89,7,5,44,44,37,44,60,21,58,51,54,17,58],[19,80,81,68,5,94,47,69,28,73,92,13,86,52,17,77,4,89,55,40],
	[4,52,8,83,97,35,99,16,7,97,57,32,16,26,26,79,33,27,98,66],[88,36,68,87,57,62,20,72,3,46,33,67,46,55,12,32,63,93,53,69],
	[4,42,16,73,38,25,39,11,24,94,72,18,8,46,29,32,40,62,76,36],[20,69,36,41,72,30,23,88,34,62,99,69,82,67,59,85,74,4,36,16],
	[20,73,35,29,78,31,90,1,74,31,49,71,48,86,81,16,23,57,5,54],[1,70,54,71,83,51,54,69,16,92,33,48,61,43,52,1,89,19,67,48]],
	subArrayMaxes, totalMax,
	directionChecks = {
		verticalCheck: function (grid) {
			var product = 1,
				distance = 0;
				for (distance; distance < grid.length; distance++) {
					product *= grid[distance][0];
				}
				return (product || 0);
		},
		horizontalCheck: function (grid) {
			var product = 1,
				distance = 0;
				for (distance; distance < grid.length; distance++) {
					product *= grid[0][distance];
				}
				return (product || 0);
		},
		diagOneCheck: function (grid) {
				var product = 1,
					distance = 0;
				for (distance; distance < grid.length; distance++) {
					product *= grid[distance][distance];
				}
				return (product || 0);		
		},
		diagTwoCheck: function (grid) {
				var product = 1,
					distance = 0;
				for (distance; distance < grid.length; distance++) {
					product *= grid[grid.length - 1 - distance][distance];
				}
				return (product || 0);
		}
	},
	checks = [directionChecks.verticalCheck, directionChecks.horizontalCheck, directionChecks.diagOneCheck, directionChecks.diagTwoCheck];
function subGrid(grid, distance) {
	var colLen = grid.length,
		rowLen = grid[0].length,
		subGrids = [],
		tempGrid = [],
		x, y = 0,
		lenCountX, lenCountY;
	//loop through all the applicable points of the array
	for (y; y < colLen; y++) {
		for (x = 0; x < rowLen; x++) {
			//from the point x, y generate the subGrid and append it to the list of grids
			for (lenCountX = 0; lenCountX < distance; lenCountX++) {
				for (lenCountY = 0; lenCountY < distance; lenCountY++) {
					if (!tempGrid[lenCountY]) {
						tempGrid[lenCountY] = [];
					}
					if (grid[y + lenCountY]) {
						tempGrid[lenCountY][lenCountX] =
							grid[y + lenCountY][x + lenCountX];
					} else {
						tempGrid[lenCountY][lenCountX] = undefined;
					}
				}
			}
			subGrids.push(tempGrid);
			tempGrid = [];
		}
	}
	return subGrids;
}

function checkSubGrids(subGrid, index, allGrids) {
	//this should be set to the an array of the checks to execute
	return this.map(function (checkFunc, index, allChecks) {
		return checkFunc(subGrid);
	});
}
// function maxOfArray(array) {
// 	return Math.max.apply(undefined, array);
// }
function maxOfArray(leadingHighest, currentNum) {
	return Math.max(leadingHighest, currentNum);
}

function largestProduct(grid, subGridSize) {
	subArrayMaxes = subGrid(grid, 4)
		.map(checkSubGrids, checks);
	totalMax = subArrayMaxes.map(function (subArrayChecks) {
		return subArrayChecks.reduce(maxOfArray, 0);
	}).reduce(maxOfArray, 0);
	return totalMax;
}
console.log(largestProduct(grid, 4));