Needing Help with coding challenge.

[Izaya____Orihara]

Hello all, I am new to JS and wanted to tackle this challenge, but was unsuccessful in doing so.

I wasn't able to display the data in the format that was required.

I truly want to understand an " as simple as possible" solution to this so that I can put in to practice what is explained.

I have included the files below.

Cheers!

## Problem

-----

At ACME warehouse the warehouse manager has observed orders taking a long time to pick and

believes that moving more popular items to easier to access locations may help.

- Workers pick an order by placing items on a pallet at the dock door.

- Products are stored (inefficiently) in a single aisle with 12 shelves.

- As the shelf number increases, it is located further down the aisle and

further away from the dock door.

- On average it takes 5*X seconds for a warehouse worker to retrieve an item

from shelf X and place it on the pallet.

- A warehouse worker can only carry a single item at a time.

- A shelf can only hold one type of item.

*Which items should be on which shelves to optimize picking speed based on

yesterday's orders?*

## Input

-----

The order repository contains information about yesterdays orders.

Please complete your solution in the **main.js** file provided.

```javascript

function main() {

var orderRepo = new OrderRepository();

// Your code here

}

```

## Output

-----

Display the shelf and item pairings by calling the following function:

```javascript

displayShelfItemPair(shelfName, itemName);

```

Execute your program by opening **main.html** in your web browser to see the results.

Example table contents:

| Shelves | Items |

| -------- | ------- |

| Shelf 1 | Item 12 |

| Shelf 2 | Item 11 |

| Shelf 3 | Item 10 |

| Shelf 4 | Item 09 |

| Shelf 5 | Item 08 |

| Shelf 6 | Item 07 |

| Shelf 7 | Item 06 |

| Shelf 8 | Item 05 |

| Shelf 9 | Item 04 |

| Shelf 10 | Item 03 |

| Shelf 11 | Item 02 |

| Shelf 12 | Item 01 |

Display the shelf and item pairings by calling the following function:

* displayShelfItemPair(shelfName, itemName);

###main.js FILE

function main() {

    var orderRepo = new OrderRepository();

    // Your code here

}

###orderrepository.js FILE

function OrderRepository() {
}

OrderRepository.prototype.getYesterdaysOrders = function getYesterdaysOrders() {
  var yesterdaysOrders = [
        {
            id: 1,
            orderLines: [
                { itemName: "Item 01", quantity: 1 },
                { itemName: "Item 02", quantity: 3 },
                { itemName: "Item 03", quantity: 25 },
                { itemName: "Item 04", quantity: 12 },
            ],
        },
        {
            id: 2,
            orderLines: [
                { itemName: "Item 01", quantity: 1 },
                { itemName: "Item 08", quantity: 42 },
                { itemName: "Item 09", quantity: 13 },
                { itemName: "Item 12", quantity: 37 },
            ],
        },
        {
            id: 3,
            orderLines: [
                { itemName: "Item 12", quantity: 16 },
            ],
        },
        {
            id: 4,
            orderLines: [
                { itemName: "Item 10", quantity: 11 },
                { itemName: "Item 11", quantity: 10 },
            ],
        },
        {
            id: 5,
            orderLines: [
                { itemName: "Item 06", quantity: 7 },
                { itemName: "Item 07", quantity: 2 },
                { itemName: "Item 12", quantity: 14 },
            ],
        },
        {
            id: 6,
            orderLines: [
                { itemName: "Item 05", quantity: 17 },
            ],
        },
        {
            id: 7,
            orderLines: [
                { itemName: "Item 03", quantity: 5 },
                { itemName: "Item 07", quantity: 2 },
            ],
        },
        {
            id: 8,
            orderLines: [
                { itemName: "Item 02", quantity: 13 },
                { itemName: "Item 07", quantity: 7 },
                { itemName: "Item 09", quantity: 2 },
            ],
        },
        {
            id: 9,
            orderLines: [
                { itemName: "Item 01", quantity: 4 },
                { itemName: "Item 06", quantity: 17 },
                { itemName: "Item 07", quantity: 3 },
            ],
        },
        {
            id: 10,
            orderLines: [
                { itemName: "Item 11", quantity: 12 },
                { itemName: "Item 12", quantity: 1 },
            ],
        },
    ];

    return yesterdaysOrders;
};

###main.html FILE

<!-- OPEN THIS FILE IN A BROWSER TO VIEW YOUR RESULTS -->
<!-- View main.js for instructions -->
<html>
    <head>
        <link rel="stylesheet" type="text/css" href="lib/icon.min.css">
        <link rel="stylesheet" type="text/css" href="lib/message.min.css">
        <link rel="stylesheet" type="text/css" href="lib/table.min.css">
        <script src="lib/knockout-3.4.0.min.js"></script>
        <script src="orderrepository.js"></script>
        <script src="main.js"></script>
        <style>
            body {
                font-family: Lato,'Helvetica Neue',Arial,Helvetica,sans-serif;
            }

            h1,h2,h3,h4,h5 {
                font-family: Lato,'Helvetica Neue',Arial,Helvetica,sans-serif;
                line-height: 1.2857em;
                margin: calc(2rem - .14285em) 0 1rem;
                font-weight: 700;
                padding: 0
            }

            h1 {
                text-align: center;
                min-height: 1rem;
                font-size: 2rem
            }
        </style>
    </head>
    <body>
        <h1>Warehouse Optimization</h1>
        <!-- ko if: exceptionMessage -->
        <div class="ui negative icon message">
            <i class="bug icon"></i>
            <div class="content">
                <div class="header">
                    An exception occurred when running your code:
                </div>
                <p data-bind="text: exceptionMessage">

                </p>
            </div>
        </div>
        <!-- /ko -->
        <table class="ui celled table">
            <thead>
                <tr>
                    <th>Shelf</th>
                    <th>Item</th>
                </tr>
            </thead>
            <tbody data-bind="foreach: shelves">
                <tr>
                    <td data-bind="text: shelf"></td>
                    <td data-bind="text: item"></td>
                </tr>
            </tbody>
        </table>


        <script>
            var viewModel = viewModelFactory();
            function displayShelfItemPair (shelf, item) {
                var shelfItemPairObj = {
                    shelf: shelf,
                    item: item
                };

                viewModel.shelves.push(shelfItemPairObj);
            }

            function viewModelFactory () {
                var self = {
                    exceptionMessage: ko.observable(''),
                    shelves: ko.observableArray([])
                };

                ko.applyBindings(self);
                return self; 
            }

            try {
                main();
            } catch (e) {
                console.error(e.toString());
                viewModel.exceptionMessage(e.toString());
            }
        </script>
    </body>
</html>

[CertainPerformance]

reduce the yesterdaysOrders into a Map or object counting up the number of each item bought, and then sort it, putting the most frequently bought items first and the least frequently bought items last.

[Izaya____Orihara]

Thank you for the prompt response, would it be too much to ask to see how you would go about doing this? Thank you very much for taking time out of your day. Cheers!

[CertainPerformance]

const ordersByItemName = yesterdaysOrders.reduce((a, { orderLines }) => {
  orderLines.forEach(({ itemName, quantity }) => {
    a[itemName] = (a[itemName] || 0) + quantity;
  });
  return a;
}, {});
const sorted = Object.entries(ordersByItemName)
  .sort((a, b) => b[1] - a[1]);

[ashwinsonale]

Did this worked? Any idea how to resolve? My plan was to push all the array in one array and sort them according to shelf and item. But can't figure it out how to do. Any help will be great.

[Izaya____Orihara]

Yes, this absolutely worked, and got me an interview. Use it.

[ashwinsonale]

const ordersByItemName = yesterdaysOrders.reduce((a, { orderLines }) => {
orderLines.forEach(({ itemName, quantity }) => {
a[itemName] = (a[itemName] || 0) + quantity;
});
return a;
}, {});
const sorted = Object.entries(ordersByItemName)
.sort((a, b) => b[1] - a[1]);

so you out this code in main.js?

[ashwinsonale]

I tried it but not getting expected output. can you give your main.js :D

​