inventory_update.md

Inventory Update

This function compares and updates the inventory stored in a 2D array against a second 2D array of a fresh delivery. If an item cannot be found, it adds the new item and quantity into the inventory array. The returned inventory array is in alphabetical order by item.

function updateInventory(arr1, arr2) {
    var newInventory = arr1.concat(arr2).reduce(function(x, y){
        if(x[y[1]])
        {
            x[y[1]] += y[0];
        }
        else
        {
            x[y[1]] = y[0];
        }
        return x;
    }, {});

    return Object.keys(newInventory).map(function(z){
        return [newInventory[z], z];
    }).sort(function(a,b){
        if(a[1] === b[1])
        {
            return 0;
        }
        else
        {
            return (a[1] < b[1]) ? -1 : 1;
        }
    });
}

var curInv = [
    [21, "Bowling Ball"],
    [2, "Dirty Sock"],
    [1, "Hair Pin"],
    [5, "Microphone"]
];

var newInv = [
    [2, "Hair Pin"],
    [3, "Half-Eaten Apple"],
    [67, "Bowling Ball"],
    [7, "Toothpaste"]
];

updateInventory(curInv, newInv);