cutlist.js

var kerf = 0.125;
var stock_length = 96;

function arraySum(arr) {
	var sum = 0;
	for (var i = 0, len = arr.length; i < len; sum += arr[i++]);
	sum += (arr.length * kerf);
	return sum;
}

/**
 * Simple Sorted Best Fit linear bin packing algorithm to figure out cut lists
 * and material needs.
 */
function calculateCutList(cut_array) {
	var stock_array = [];

	// Sort cuts largest to smallest
	cut_array.sort((a, b) => b - a);

	cut_array.forEach(cut => {
		// Track reference to best-fit stock array and the leftover space after this cut is fit
		var bestStock = null;
		var bestLeftover = stock_length;

		stock_array.forEach(stock => {
			// Calculate how much space is used and what is available
			var used = arraySum(stock);
			var avail = stock_length - used - kerf;

			// If there is space available for the cut
			if (cut <= avail) {
				var leftover = avail - cut;

				// If the leftover is less than the existing best stock
				if (leftover < bestLeftover) {
					// Capture ref to stock array and leftover space
					bestStock = stock;
					bestLeftover = leftover;
				}
			}
		});

		// If no bestStock is found add a new stock with the cut
		if (bestStock == null) {
			stock_array.push([cut]);
		} else {
			// Otherwise add the cut to the best fitting stock
			bestStock.push(cut);
		}
	});


	stock_array.sort((a, b) => arraySum(b) - arraySum(a));
	stock_array.forEach(stock => console.log(stock));
}

console.log("2x6");
calculateCutList([32.5,32.5,32.5,32.5,27,27,27,27,29,29,72,72,34.5,34.5]);
console.log("2x4");
calculateCutList([25,25,25,25,25,34,34,34,34,57.375,57.375,72,41,33,33,19.625,19.625,10.5,10.5,17.5,17.5,29,29,5.1875,5.1875,5.1875,5.1875]);
console.log("1x4");
calculateCutList([2.25,2.25,23.625,23.625,36,36,41,73.5,20.5]);