ptdecker/index.html

## index.html
<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JS Bin</title>
</head>
<body>

<script id="jsbin-javascript">
// Configuration values that are global to the store. These would need
// some sort of a Magento dialog to allow the business team to maintain
// them. Values are stored in cents to avoid JavaScript floating point
// issues
//
// standardShippingRate
//      The amount of shipping that should be charged on a per item
//      basis unless the individual SKU has a special shipping charge
// freeShippingThreshold
//      The amount of the sub-total of the cart of the items that do
//      not have special shipping charges that, once exceeded, will
//      result in a zero charge for shipping of the items that do not
//      have the special shipping charges

var globalSettings = {
  standardShippingRate: 500,
  freeShippingThreshold: 12000
};

// Sample product catalog. Of course, in a real implementation, these
// items would come from the product catalog database. And, the logic
// around the price I'm sure has additional considerations. But, the
// important new piece here is 'specialShippingCharge'. The product
// inventory maintenance pages in the back-end would need to have a place
// where the business team can set this 'specialShippingCharge' for
// each item.
//
// sku
//      Unique identifier for the product catalog item
// price
//      The integer price in cents (to avoid floating point problems in
//      JavaScipt) for one unit of the item
// specialShippingCharge
//      If this amount is defined (or is not zero in strong typed
//      languages), then this amount defines the amount of shipping that
//      is always charged for this item.

var productCatalog = {
  items: [
    {
      sku: "12345",
      price: 1000
    },{
      sku: "67890",
      price: 1500
    },{
      sku: "23456",
      price: 10500,
      specialShippingCharge: 7500
    },{
      sku: "78901",
      price: 12500
    },{
      sku: "34567",
      price: 750,
      specialShippingCharge: 500
    }
  ]
};

// Various sample chopping carts


// Empty cart

var sampleCartA = {
  description: "Empty cart",
  items: []
};

// Cart containing no special shipping items

var sampleCartB = {
  description: "Cart containing no special shipping items",
  items: [
    {
      sku:"12345",
      quantity: 3
    },{
      sku:"67890",
      quantity: 2
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing no special shipping items but where the subtotal of
// the items exceeds the free shipping threshold.

var sampleCartC = {
  description: "Cart containing no special shipping items but where the subtotal of the items exceeds the free shipping threshold",
  items: [
    {
      sku:"12345",
      quantity: 30
    },{
      sku:"67890",
      quantity: 2
    }
  ]
};

// Cart containing special shipping items

var sampleCartD = {
  description: "Cart containing special shipping items",
  items: [
    {
      sku:"23456",
      quantity: 1
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing a mix of regular and special shipping items

var sampleCartE = {
  description: "Cart containing a mix of regular and special shipping items",
  items: [
    {
      sku:"12345",
      quantity: 3
    },{
      sku:"67890",
      quantity: 2
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing a mix of regular and special shipping items where the
// subtotal of the regular items exceeds the free shipping theshold.

var sampleCartF = {
  description: "Cart containing a mix of regular and special shipping items where the subtotal of the regular items exceeds the free shipping theshold",
  items: [
    {
      sku:"12345",
      quantity:30
    },{
      sku:"67890",
      quantity:2
    },{
      sku:"23456",
      quantity: 2
    }
  ]
};


// Helper function to left pad a string with a character to a width
// Credit for this goes to: http://stackoverflow.com/a/9744576/959570

function paddy(n, p, c) {
    var pad_char = typeof c !== 'undefined' ? c : '0';
    var pad = new Array(1 + p).join(pad_char);
    return (pad + n).slice(-pad.length);
}

// Helper function to add commas using U.S. format pattern (9,999,999)
// Credit for this goes to: http://stackoverflow.com/a/2901298/3893444

function addCommas(value) {
  return value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

// A type-safe helper function to nicely format a string to a width.
// Strings that are wider than the width are displayed as a width-wide
// string of 'x'. If passed a non-string value, the value is returned
// unaltered.

function formatString(value, width) {
  if (typeof value !== 'string') {
    return value;
  }
  if (value.length > width) {
    return paddy('', width, 'x');
  } else {
    return paddy(value, width, ' ');
  }
}

// Helper function to nicely format currency based upon an integer
// currency value where the least significant two digits represent cents
// using U.S. format pattern ($ 9,999.99). Values that overflow the width
// are displayed as a width-wide string of 'x'.

function formatCurrency(value, width) {
  var dollars = Math.floor(value / 100);
  var cents = value % 100;
  var formatted = addCommas(dollars) + "." + paddy(cents, 2, "0");
  if (formatted.length + 1 > width) {
    return paddy('', width, 'x');
  } else {
    return '$' + paddy(formatted, width - 1, ' ');
  }
}

// Helper function to nicely format integers. Values that overflow the
// width are displayed as a width-wide string of 'x'.

function formatInteger(value, width) {
  if (value.length > width) {
    return paddy('', width, 'x');
  } else {
    return paddy(value, width, ' ');
  }
}

// Helper function to look up a SKU from the product catalog
// Notes: This is a really stupid O(n) approach, but for this demo it
// works fine

function getSKU(sku, catalog) {
  var result = {},
      skuTemp,
      index,
      size;
  for (index = 0, size = catalog.items.length; index < size; index += 1) {
    skuTemp = catalog.items[index].sku;
    if (skuTemp !== undefined && skuTemp === sku) {
      return catalog.items[index];
    }
  }
  return undefined;
}

// Add unit prices to the items in the cart

function addUnitPrices(cart, catalog) {
  var newItems = cart.items.map(function(item){
    var newItem = item,
        itemDetail = getSKU(item.sku, catalog),
        unitPrice;
    if (itemDetail === undefined || itemDetail.price === undefined) {
      newItem.unitPrice = 0;
    } else {
      newItem.unitPrice = itemDetail.price;
    }
    return newItem;
  });
  return newItems;
}


// Calculate extended prices

function extendPrices(cart) {
  var newItems = cart.items.map(function(item){
    var newItem = item;
    item.extendedPrice = item.unitPrice * item.quantity;
    return newItem;
  });
  return newItems;

}

// Calculate cart sub-total

function calcSubtotal(cart) {
  cart.subtotal = 0;
  cart.items.forEach(function(item) {
    cart.subtotal += item.extendedPrice;
  });
}

// Add shipping costs to the cart

function addShipping(cart, globals, catalog) {

  var regularShippingTotal = 0,  // Accumulated regular shipping expenses
      specialShippingTotal = 0;  // Accumulated special shipping expense

  // Spin through the items in the shopping cart evaluating the shipping
  // charge situation for each.

  cart.items.forEach(function(item) {

    // Look up the special shipping amount for the current cart item

    var specialShipping = getSKU(item.sku, catalog).specialShippingCharge;

    // If there is 'special shipping' amount for the item then add the
    // accumualted special shipping charges. Otherwise, add the global
    // regular shipping fee to the accumulated regular shipping charges.
    // Of course, both the above taking into account quanity.

    if (specialShipping !== undefined && specialShipping !== 0) {
      specialShippingTotal += specialShipping * item.quantity;
    } else {
      regularShippingTotal += globals.standardShippingRate * item.quantity;
    }
  });

  // Now that all items have been evaluated, if accumulated regular
  // shipping is over the global free shipping threshold then give
  // the customer free shipping.

  if (cart.subtotal > globals.freeShippingThreshold) {
    regularShippingTotal = 0;
  }

  // Final shipping amount equals regular plus special shipping

  cart.shipping = regularShippingTotal + specialShippingTotal;

}

// Calculate the cart total

function calcTotal(cart) {
  cart.total = cart.subtotal + cart.shipping;
}

// Calculate the cart

function calculateCart(cart, global, catalog) {
  addUnitPrices(cart, catalog);
  extendPrices(cart);
  calcSubtotal(cart);
  addShipping(cart, global, catalog);
  calcTotal(cart);
}

// Display the contents of a cart on the console

function showCartOnConsole(cart) {
  console.log(cart.description);
  if (cart.items.length === 0) {
    console.log("The cart is empty");
  } else {
    cart.items.forEach(function(item) {
      console.log(
        formatString(item.sku, 6) + " " +
        formatCurrency(item.unitPrice, 10) + " " +
        formatInteger(item.quantity, 6) + " " +
        formatCurrency(item.extendedPrice, 10)
      );
    });
    console.log(
      formatString("Subtotal", 10) + " " +
      formatCurrency(cart.subtotal, 10)
    );
    console.log(
      formatString("Shipping", 10) + " " +
      formatCurrency(cart.shipping, 10)
    );
    console.log(
      formatString("Total", 10) + " " +
      formatCurrency(cart.total, 10)
    );
  }
  console.log("");
}

// Calculate test carts and show the results.

calculateCart(sampleCartA, globalSettings, productCatalog);
showCartOnConsole(sampleCartA);

calculateCart(sampleCartB, globalSettings, productCatalog);
showCartOnConsole(sampleCartB);

calculateCart(sampleCartC, globalSettings, productCatalog);
showCartOnConsole(sampleCartC);

calculateCart(sampleCartD, globalSettings, productCatalog);
showCartOnConsole(sampleCartD);

calculateCart(sampleCartE, globalSettings, productCatalog);
showCartOnConsole(sampleCartE);

calculateCart(sampleCartF, globalSettings, productCatalog);
showCartOnConsole(sampleCartF);
</script>


<script id="jsbin-source-javascript" type="text/javascript">// Configuration values that are global to the store. These would need
// some sort of a Magento dialog to allow the business team to maintain
// them. Values are stored in cents to avoid JavaScript floating point
// issues
//
// standardShippingRate
//      The amount of shipping that should be charged on a per item
//      basis unless the individual SKU has a special shipping charge
// freeShippingThreshold
//      The amount of the sub-total of the cart of the items that do
//      not have special shipping charges that, once exceeded, will
//      result in a zero charge for shipping of the items that do not
//      have the special shipping charges

var globalSettings = {
  standardShippingRate: 500,
  freeShippingThreshold: 12000
};

// Sample product catalog. Of course, in a real implementation, these
// items would come from the product catalog database. And, the logic
// around the price I'm sure has additional considerations. But, the
// important new piece here is 'specialShippingCharge'. The product
// inventory maintenance pages in the back-end would need to have a place
// where the business team can set this 'specialShippingCharge' for
// each item.
//
// sku
//      Unique identifier for the product catalog item
// price
//      The integer price in cents (to avoid floating point problems in
//      JavaScipt) for one unit of the item
// specialShippingCharge
//      If this amount is defined (or is not zero in strong typed
//      languages), then this amount defines the amount of shipping that
//      is always charged for this item.

var productCatalog = {
  items: [
    {
      sku: "12345",
      price: 1000
    },{
      sku: "67890",
      price: 1500
    },{
      sku: "23456",
      price: 10500,
      specialShippingCharge: 7500
    },{
      sku: "78901",
      price: 12500
    },{
      sku: "34567",
      price: 750,
      specialShippingCharge: 500
    }
  ]
};

// Various sample chopping carts


// Empty cart

var sampleCartA = {
  description: "Empty cart",
  items: []
};

// Cart containing no special shipping items

var sampleCartB = {
  description: "Cart containing no special shipping items",
  items: [
    {
      sku:"12345",
      quantity: 3
    },{
      sku:"67890",
      quantity: 2
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing no special shipping items but where the subtotal of
// the items exceeds the free shipping threshold.

var sampleCartC = {
  description: "Cart containing no special shipping items but where the subtotal of the items exceeds the free shipping threshold",
  items: [
    {
      sku:"12345",
      quantity: 30
    },{
      sku:"67890",
      quantity: 2
    }
  ]
};

// Cart containing special shipping items

var sampleCartD = {
  description: "Cart containing special shipping items",
  items: [
    {
      sku:"23456",
      quantity: 1
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing a mix of regular and special shipping items

var sampleCartE = {
  description: "Cart containing a mix of regular and special shipping items",
  items: [
    {
      sku:"12345",
      quantity: 3
    },{
      sku:"67890",
      quantity: 2
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing a mix of regular and special shipping items where the
// subtotal of the regular items exceeds the free shipping theshold.

var sampleCartF = {
  description: "Cart containing a mix of regular and special shipping items where the subtotal of the regular items exceeds the free shipping theshold",
  items: [
    {
      sku:"12345",
      quantity:30
    },{
      sku:"67890",
      quantity:2
    },{
      sku:"23456",
      quantity: 2
    }
  ]
};


// Helper function to left pad a string with a character to a width
// Credit for this goes to: http://stackoverflow.com/a/9744576/959570

function paddy(n, p, c) {
    var pad_char = typeof c !== 'undefined' ? c : '0';
    var pad = new Array(1 + p).join(pad_char);
    return (pad + n).slice(-pad.length);
}

// Helper function to add commas using U.S. format pattern (9,999,999)
// Credit for this goes to: http://stackoverflow.com/a/2901298/3893444

function addCommas(value) {
  return value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

// A type-safe helper function to nicely format a string to a width.
// Strings that are wider than the width are displayed as a width-wide
// string of 'x'. If passed a non-string value, the value is returned
// unaltered.

function formatString(value, width) {
  if (typeof value !== 'string') {
    return value;
  }
  if (value.length > width) {
    return paddy('', width, 'x');
  } else {
    return paddy(value, width, ' ');
  }
}

// Helper function to nicely format currency based upon an integer
// currency value where the least significant two digits represent cents
// using U.S. format pattern ($ 9,999.99). Values that overflow the width
// are displayed as a width-wide string of 'x'.

function formatCurrency(value, width) {
  var dollars = Math.floor(value / 100);
  var cents = value % 100;
  var formatted = addCommas(dollars) + "." + paddy(cents, 2, "0");
  if (formatted.length + 1 > width) {
    return paddy('', width, 'x');
  } else {
    return '$' + paddy(formatted, width - 1, ' ');
  }
}

// Helper function to nicely format integers. Values that overflow the
// width are displayed as a width-wide string of 'x'.

function formatInteger(value, width) {
  if (value.length > width) {
    return paddy('', width, 'x');
  } else {
    return paddy(value, width, ' ');
  }
}

// Helper function to look up a SKU from the product catalog
// Notes: This is a really stupid O(n) approach, but for this demo it
// works fine

function getSKU(sku, catalog) {
  var result = {},
      skuTemp,
      index,
      size;
  for (index = 0, size = catalog.items.length; index < size; index += 1) {
    skuTemp = catalog.items[index].sku;
    if (skuTemp !== undefined && skuTemp === sku) {
      return catalog.items[index];
    }
  }
  return undefined;
}

// Add unit prices to the items in the cart

function addUnitPrices(cart, catalog) {
  var newItems = cart.items.map(function(item){
    var newItem = item,
        itemDetail = getSKU(item.sku, catalog),
        unitPrice;
    if (itemDetail === undefined || itemDetail.price === undefined) {
      newItem.unitPrice = 0;
    } else {
      newItem.unitPrice = itemDetail.price;
    }
    return newItem;
  });
  return newItems;
}


// Calculate extended prices

function extendPrices(cart) {
  var newItems = cart.items.map(function(item){
    var newItem = item;
    item.extendedPrice = item.unitPrice * item.quantity;
    return newItem;
  });
  return newItems;

}

// Calculate cart sub-total

function calcSubtotal(cart) {
  cart.subtotal = 0;
  cart.items.forEach(function(item) {
    cart.subtotal += item.extendedPrice;
  });
}

// Add shipping costs to the cart

function addShipping(cart, globals, catalog) {

  var regularShippingTotal = 0,  // Accumulated regular shipping expenses
      specialShippingTotal = 0;  // Accumulated special shipping expense

  // Spin through the items in the shopping cart evaluating the shipping
  // charge situation for each.

  cart.items.forEach(function(item) {

    // Look up the special shipping amount for the current cart item

    var specialShipping = getSKU(item.sku, catalog).specialShippingCharge;

    // If there is 'special shipping' amount for the item then add the
    // accumualted special shipping charges. Otherwise, add the global
    // regular shipping fee to the accumulated regular shipping charges.
    // Of course, both the above taking into account quanity.

    if (specialShipping !== undefined && specialShipping !== 0) {
      specialShippingTotal += specialShipping * item.quantity;
    } else {
      regularShippingTotal += globals.standardShippingRate * item.quantity;
    }
  });

  // Now that all items have been evaluated, if accumulated regular
  // shipping is over the global free shipping threshold then give
  // the customer free shipping.

  if (cart.subtotal > globals.freeShippingThreshold) {
    regularShippingTotal = 0;
  }

  // Final shipping amount equals regular plus special shipping

  cart.shipping = regularShippingTotal + specialShippingTotal;

}

// Calculate the cart total

function calcTotal(cart) {
  cart.total = cart.subtotal + cart.shipping;
}

// Calculate the cart

function calculateCart(cart, global, catalog) {
  addUnitPrices(cart, catalog);
  extendPrices(cart);
  calcSubtotal(cart);
  addShipping(cart, global, catalog);
  calcTotal(cart);
}

// Display the contents of a cart on the console

function showCartOnConsole(cart) {
  console.log(cart.description);
  if (cart.items.length === 0) {
    console.log("The cart is empty");
  } else {
    cart.items.forEach(function(item) {
      console.log(
        formatString(item.sku, 6) + " " +
        formatCurrency(item.unitPrice, 10) + " " +
        formatInteger(item.quantity, 6) + " " +
        formatCurrency(item.extendedPrice, 10)
      );
    });
    console.log(
      formatString("Subtotal", 10) + " " +
      formatCurrency(cart.subtotal, 10)
    );
    console.log(
      formatString("Shipping", 10) + " " +
      formatCurrency(cart.shipping, 10)
    );
    console.log(
      formatString("Total", 10) + " " +
      formatCurrency(cart.total, 10)
    );
  }
  console.log("");
}

// Calculate test carts and show the results.

calculateCart(sampleCartA, globalSettings, productCatalog);
showCartOnConsole(sampleCartA);

calculateCart(sampleCartB, globalSettings, productCatalog);
showCartOnConsole(sampleCartB);

calculateCart(sampleCartC, globalSettings, productCatalog);
showCartOnConsole(sampleCartC);

calculateCart(sampleCartD, globalSettings, productCatalog);
showCartOnConsole(sampleCartD);

calculateCart(sampleCartE, globalSettings, productCatalog);
showCartOnConsole(sampleCartE);

calculateCart(sampleCartF, globalSettings, productCatalog);
showCartOnConsole(sampleCartF);</script></body>
</html>

## jsbin.fuzomo.js
// Configuration values that are global to the store. These would need
// some sort of a Magento dialog to allow the business team to maintain
// them. Values are stored in cents to avoid JavaScript floating point
// issues
//
// standardShippingRate
//      The amount of shipping that should be charged on a per item
//      basis unless the individual SKU has a special shipping charge
// freeShippingThreshold
//      The amount of the sub-total of the cart of the items that do
//      not have special shipping charges that, once exceeded, will
//      result in a zero charge for shipping of the items that do not
//      have the special shipping charges

var globalSettings = {
  standardShippingRate: 500,
  freeShippingThreshold: 12000
};

// Sample product catalog. Of course, in a real implementation, these
// items would come from the product catalog database. And, the logic
// around the price I'm sure has additional considerations. But, the
// important new piece here is 'specialShippingCharge'. The product
// inventory maintenance pages in the back-end would need to have a place
// where the business team can set this 'specialShippingCharge' for
// each item.
//
// sku
//      Unique identifier for the product catalog item
// price
//      The integer price in cents (to avoid floating point problems in
//      JavaScipt) for one unit of the item
// specialShippingCharge
//      If this amount is defined (or is not zero in strong typed
//      languages), then this amount defines the amount of shipping that
//      is always charged for this item.

var productCatalog = {
  items: [
    {
      sku: "12345",
      price: 1000
    },{
      sku: "67890",
      price: 1500
    },{
      sku: "23456",
      price: 10500,
      specialShippingCharge: 7500
    },{
      sku: "78901",
      price: 12500
    },{
      sku: "34567",
      price: 750,
      specialShippingCharge: 500
    }
  ]
};

// Various sample chopping carts


// Empty cart

var sampleCartA = {
  description: "Empty cart",
  items: []
};

// Cart containing no special shipping items

var sampleCartB = {
  description: "Cart containing no special shipping items",
  items: [
    {
      sku:"12345",
      quantity: 3
    },{
      sku:"67890",
      quantity: 2
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing no special shipping items but where the subtotal of
// the items exceeds the free shipping threshold.

var sampleCartC = {
  description: "Cart containing no special shipping items but where the subtotal of the items exceeds the free shipping threshold",
  items: [
    {
      sku:"12345",
      quantity: 30
    },{
      sku:"67890",
      quantity: 2
    }
  ]
};

// Cart containing special shipping items

var sampleCartD = {
  description: "Cart containing special shipping items",
  items: [
    {
      sku:"23456",
      quantity: 1
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing a mix of regular and special shipping items

var sampleCartE = {
  description: "Cart containing a mix of regular and special shipping items",
  items: [
    {
      sku:"12345",
      quantity: 3
    },{
      sku:"67890",
      quantity: 2
    },{
      sku:"34567",
      quantity: 2
    }
  ]
};

// Cart containing a mix of regular and special shipping items where the
// subtotal of the regular items exceeds the free shipping theshold.

var sampleCartF = {
  description: "Cart containing a mix of regular and special shipping items where the subtotal of the regular items exceeds the free shipping theshold",
  items: [
    {
      sku:"12345",
      quantity:30
    },{
      sku:"67890",
      quantity:2
    },{
      sku:"23456",
      quantity: 2
    }
  ]
};


// Helper function to left pad a string with a character to a width
// Credit for this goes to: http://stackoverflow.com/a/9744576/959570

function paddy(n, p, c) {
    var pad_char = typeof c !== 'undefined' ? c : '0';
    var pad = new Array(1 + p).join(pad_char);
    return (pad + n).slice(-pad.length);
}

// Helper function to add commas using U.S. format pattern (9,999,999)
// Credit for this goes to: http://stackoverflow.com/a/2901298/3893444

function addCommas(value) {
  return value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
}

// A type-safe helper function to nicely format a string to a width.
// Strings that are wider than the width are displayed as a width-wide
// string of 'x'. If passed a non-string value, the value is returned
// unaltered.

function formatString(value, width) {
  if (typeof value !== 'string') {
    return value;
  }
  if (value.length > width) {
    return paddy('', width, 'x');
  } else {
    return paddy(value, width, ' ');
  }
}

// Helper function to nicely format currency based upon an integer
// currency value where the least significant two digits represent cents
// using U.S. format pattern ($ 9,999.99). Values that overflow the width
// are displayed as a width-wide string of 'x'.

function formatCurrency(value, width) {
  var dollars = Math.floor(value / 100);
  var cents = value % 100;
  var formatted = addCommas(dollars) + "." + paddy(cents, 2, "0");
  if (formatted.length + 1 > width) {
    return paddy('', width, 'x');
  } else {
    return '$' + paddy(formatted, width - 1, ' ');
  }
}

// Helper function to nicely format integers. Values that overflow the
// width are displayed as a width-wide string of 'x'.

function formatInteger(value, width) {
  if (value.length > width) {
    return paddy('', width, 'x');
  } else {
    return paddy(value, width, ' ');
  }
}

// Helper function to look up a SKU from the product catalog
// Notes: This is a really stupid O(n) approach, but for this demo it
// works fine

function getSKU(sku, catalog) {
  var result = {},
      skuTemp,
      index,
      size;
  for (index = 0, size = catalog.items.length; index < size; index += 1) {
    skuTemp = catalog.items[index].sku;
    if (skuTemp !== undefined && skuTemp === sku) {
      return catalog.items[index];
    }
  }
  return undefined;
}

// Add unit prices to the items in the cart

function addUnitPrices(cart, catalog) {
  var newItems = cart.items.map(function(item){
    var newItem = item,
        itemDetail = getSKU(item.sku, catalog),
        unitPrice;
    if (itemDetail === undefined || itemDetail.price === undefined) {
      newItem.unitPrice = 0;
    } else {
      newItem.unitPrice = itemDetail.price;
    }
    return newItem;
  });
  return newItems;
}


// Calculate extended prices

function extendPrices(cart) {
  var newItems = cart.items.map(function(item){
    var newItem = item;
    item.extendedPrice = item.unitPrice * item.quantity;
    return newItem;
  });
  return newItems;

}

// Calculate cart sub-total

function calcSubtotal(cart) {
  cart.subtotal = 0;
  cart.items.forEach(function(item) {
    cart.subtotal += item.extendedPrice;
  });
}

// Add shipping costs to the cart

function addShipping(cart, globals, catalog) {

  var regularShippingTotal = 0,  // Accumulated regular shipping expenses
      specialShippingTotal = 0;  // Accumulated special shipping expense

  // Spin through the items in the shopping cart evaluating the shipping
  // charge situation for each.

  cart.items.forEach(function(item) {

    // Look up the special shipping amount for the current cart item

    var specialShipping = getSKU(item.sku, catalog).specialShippingCharge;

    // If there is 'special shipping' amount for the item then add the
    // accumualted special shipping charges. Otherwise, add the global
    // regular shipping fee to the accumulated regular shipping charges.
    // Of course, both the above taking into account quanity.

    if (specialShipping !== undefined && specialShipping !== 0) {
      specialShippingTotal += specialShipping * item.quantity;
    } else {
      regularShippingTotal += globals.standardShippingRate * item.quantity;
    }
  });

  // Now that all items have been evaluated, if accumulated regular
  // shipping is over the global free shipping threshold then give
  // the customer free shipping.

  if (cart.subtotal > globals.freeShippingThreshold) {
    regularShippingTotal = 0;
  }

  // Final shipping amount equals regular plus special shipping

  cart.shipping = regularShippingTotal + specialShippingTotal;

}

// Calculate the cart total

function calcTotal(cart) {
  cart.total = cart.subtotal + cart.shipping;
}

// Calculate the cart

function calculateCart(cart, global, catalog) {
  addUnitPrices(cart, catalog);
  extendPrices(cart);
  calcSubtotal(cart);
  addShipping(cart, global, catalog);
  calcTotal(cart);
}

// Display the contents of a cart on the console

function showCartOnConsole(cart) {
  console.log(cart.description);
  if (cart.items.length === 0) {
    console.log("The cart is empty");
  } else {
    cart.items.forEach(function(item) {
      console.log(
        formatString(item.sku, 6) + " " +
        formatCurrency(item.unitPrice, 10) + " " +
        formatInteger(item.quantity, 6) + " " +
        formatCurrency(item.extendedPrice, 10)
      );
    });
    console.log(
      formatString("Subtotal", 10) + " " +
      formatCurrency(cart.subtotal, 10)
    );
    console.log(
      formatString("Shipping", 10) + " " +
      formatCurrency(cart.shipping, 10)
    );
    console.log(
      formatString("Total", 10) + " " +
      formatCurrency(cart.total, 10)
    );
  }
  console.log("");
}

// Calculate test carts and show the results.

calculateCart(sampleCartA, globalSettings, productCatalog);
showCartOnConsole(sampleCartA);

calculateCart(sampleCartB, globalSettings, productCatalog);
showCartOnConsole(sampleCartB);

calculateCart(sampleCartC, globalSettings, productCatalog);
showCartOnConsole(sampleCartC);

calculateCart(sampleCartD, globalSettings, productCatalog);
showCartOnConsole(sampleCartD);

calculateCart(sampleCartE, globalSettings, productCatalog);
showCartOnConsole(sampleCartE);

calculateCart(sampleCartF, globalSettings, productCatalog);
showCartOnConsole(sampleCartF);
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<title>JS Bin</title>
	</head>
	<body>

	<script id="jsbin-javascript">
	// Configuration values that are global to the store. These would need
	// some sort of a Magento dialog to allow the business team to maintain
	// them. Values are stored in cents to avoid JavaScript floating point
	// issues
	//
	// standardShippingRate
	// The amount of shipping that should be charged on a per item
	// basis unless the individual SKU has a special shipping charge
	// freeShippingThreshold
	// The amount of the sub-total of the cart of the items that do
	// not have special shipping charges that, once exceeded, will
	// result in a zero charge for shipping of the items that do not
	// have the special shipping charges

	var globalSettings = {
	standardShippingRate: 500,
	freeShippingThreshold: 12000
	};

	// Sample product catalog. Of course, in a real implementation, these
	// items would come from the product catalog database. And, the logic
	// around the price I'm sure has additional considerations. But, the
	// important new piece here is 'specialShippingCharge'. The product
	// inventory maintenance pages in the back-end would need to have a place
	// where the business team can set this 'specialShippingCharge' for
	// each item.
	//
	// sku
	// Unique identifier for the product catalog item
	// price
	// The integer price in cents (to avoid floating point problems in
	// JavaScipt) for one unit of the item
	// specialShippingCharge
	// If this amount is defined (or is not zero in strong typed
	// languages), then this amount defines the amount of shipping that
	// is always charged for this item.

	var productCatalog = {
	items: [
	{
	sku: "12345",
	price: 1000
	},{
	sku: "67890",
	price: 1500
	},{
	sku: "23456",
	price: 10500,
	specialShippingCharge: 7500
	},{
	sku: "78901",
	price: 12500
	},{
	sku: "34567",
	price: 750,
	specialShippingCharge: 500
	}
	]
	};

	// Various sample chopping carts


	// Empty cart

	var sampleCartA = {
	description: "Empty cart",
	items: []
	};

	// Cart containing no special shipping items

	var sampleCartB = {
	description: "Cart containing no special shipping items",
	items: [
	{
	sku:"12345",
	quantity: 3
	},{
	sku:"67890",
	quantity: 2
	},{
	sku:"34567",
	quantity: 2
	}
	]
	};

	// Cart containing no special shipping items but where the subtotal of
	// the items exceeds the free shipping threshold.

	var sampleCartC = {
	description: "Cart containing no special shipping items but where the subtotal of the items exceeds the free shipping threshold",
	items: [
	{
	sku:"12345",
	quantity: 30
	},{
	sku:"67890",
	quantity: 2
	}
	]
	};

	// Cart containing special shipping items

	var sampleCartD = {
	description: "Cart containing special shipping items",
	items: [
	{
	sku:"23456",
	quantity: 1
	},{
	sku:"34567",
	quantity: 2
	}
	]
	};

	// Cart containing a mix of regular and special shipping items

	var sampleCartE = {
	description: "Cart containing a mix of regular and special shipping items",
	items: [
	{
	sku:"12345",
	quantity: 3
	},{
	sku:"67890",
	quantity: 2
	},{
	sku:"34567",
	quantity: 2
	}
	]
	};

	// Cart containing a mix of regular and special shipping items where the
	// subtotal of the regular items exceeds the free shipping theshold.

	var sampleCartF = {
	description: "Cart containing a mix of regular and special shipping items where the subtotal of the regular items exceeds the free shipping theshold",
	items: [
	{
	sku:"12345",
	quantity:30
	},{
	sku:"67890",
	quantity:2
	},{
	sku:"23456",
	quantity: 2
	}
	]
	};


	// Helper function to left pad a string with a character to a width
	// Credit for this goes to: http://stackoverflow.com/a/9744576/959570

	function paddy(n, p, c) {
	var pad_char = typeof c !== 'undefined' ? c : '0';
	var pad = new Array(1 + p).join(pad_char);
	return (pad + n).slice(-pad.length);
	}

	// Helper function to add commas using U.S. format pattern (9,999,999)
	// Credit for this goes to: http://stackoverflow.com/a/2901298/3893444

	function addCommas(value) {
	return value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
	}

	// A type-safe helper function to nicely format a string to a width.
	// Strings that are wider than the width are displayed as a width-wide
	// string of 'x'. If passed a non-string value, the value is returned
	// unaltered.

	function formatString(value, width) {
	if (typeof value !== 'string') {
	return value;
	}
	if (value.length > width) {
	return paddy('', width, 'x');
	} else {
	return paddy(value, width, ' ');
	}
	}

	// Helper function to nicely format currency based upon an integer
	// currency value where the least significant two digits represent cents
	// using U.S. format pattern ($ 9,999.99). Values that overflow the width
	// are displayed as a width-wide string of 'x'.

	function formatCurrency(value, width) {
	var dollars = Math.floor(value / 100);
	var cents = value % 100;
	var formatted = addCommas(dollars) + "." + paddy(cents, 2, "0");
	if (formatted.length + 1 > width) {
	return paddy('', width, 'x');
	} else {
	return '$' + paddy(formatted, width - 1, ' ');
	}
	}

	// Helper function to nicely format integers. Values that overflow the
	// width are displayed as a width-wide string of 'x'.

	function formatInteger(value, width) {
	if (value.length > width) {
	return paddy('', width, 'x');
	} else {
	return paddy(value, width, ' ');
	}
	}

	// Helper function to look up a SKU from the product catalog
	// Notes: This is a really stupid O(n) approach, but for this demo it
	// works fine

	function getSKU(sku, catalog) {
	var result = {},
	skuTemp,
	index,
	size;
	for (index = 0, size = catalog.items.length; index < size; index += 1) {
	skuTemp = catalog.items[index].sku;
	if (skuTemp !== undefined && skuTemp === sku) {
	return catalog.items[index];
	}
	}
	return undefined;
	}

	// Add unit prices to the items in the cart

	function addUnitPrices(cart, catalog) {
	var newItems = cart.items.map(function(item){
	var newItem = item,
	itemDetail = getSKU(item.sku, catalog),
	unitPrice;
	if (itemDetail === undefined \|\| itemDetail.price === undefined) {
	newItem.unitPrice = 0;
	} else {
	newItem.unitPrice = itemDetail.price;
	}
	return newItem;
	});
	return newItems;
	}


	// Calculate extended prices

	function extendPrices(cart) {
	var newItems = cart.items.map(function(item){
	var newItem = item;
	item.extendedPrice = item.unitPrice * item.quantity;
	return newItem;
	});
	return newItems;

	}

	// Calculate cart sub-total

	function calcSubtotal(cart) {
	cart.subtotal = 0;
	cart.items.forEach(function(item) {
	cart.subtotal += item.extendedPrice;
	});
	}

	// Add shipping costs to the cart

	function addShipping(cart, globals, catalog) {

	var regularShippingTotal = 0, // Accumulated regular shipping expenses
	specialShippingTotal = 0; // Accumulated special shipping expense

	// Spin through the items in the shopping cart evaluating the shipping
	// charge situation for each.

	cart.items.forEach(function(item) {

	// Look up the special shipping amount for the current cart item

	var specialShipping = getSKU(item.sku, catalog).specialShippingCharge;

	// If there is 'special shipping' amount for the item then add the
	// accumualted special shipping charges. Otherwise, add the global
	// regular shipping fee to the accumulated regular shipping charges.
	// Of course, both the above taking into account quanity.

	if (specialShipping !== undefined && specialShipping !== 0) {
	specialShippingTotal += specialShipping * item.quantity;
	} else {
	regularShippingTotal += globals.standardShippingRate * item.quantity;
	}
	});

	// Now that all items have been evaluated, if accumulated regular
	// shipping is over the global free shipping threshold then give
	// the customer free shipping.

	if (cart.subtotal > globals.freeShippingThreshold) {
	regularShippingTotal = 0;
	}

	// Final shipping amount equals regular plus special shipping

	cart.shipping = regularShippingTotal + specialShippingTotal;

	}

	// Calculate the cart total

	function calcTotal(cart) {
	cart.total = cart.subtotal + cart.shipping;
	}

	// Calculate the cart

	function calculateCart(cart, global, catalog) {
	addUnitPrices(cart, catalog);
	extendPrices(cart);
	calcSubtotal(cart);
	addShipping(cart, global, catalog);
	calcTotal(cart);
	}

	// Display the contents of a cart on the console

	function showCartOnConsole(cart) {
	console.log(cart.description);
	if (cart.items.length === 0) {
	console.log("The cart is empty");
	} else {
	cart.items.forEach(function(item) {
	console.log(
	formatString(item.sku, 6) + " " +
	formatCurrency(item.unitPrice, 10) + " " +
	formatInteger(item.quantity, 6) + " " +
	formatCurrency(item.extendedPrice, 10)
	);
	});
	console.log(
	formatString("Subtotal", 10) + " " +
	formatCurrency(cart.subtotal, 10)
	);
	console.log(
	formatString("Shipping", 10) + " " +
	formatCurrency(cart.shipping, 10)
	);
	console.log(
	formatString("Total", 10) + " " +
	formatCurrency(cart.total, 10)
	);
	}
	console.log("");
	}

	// Calculate test carts and show the results.

	calculateCart(sampleCartA, globalSettings, productCatalog);
	showCartOnConsole(sampleCartA);

	calculateCart(sampleCartB, globalSettings, productCatalog);
	showCartOnConsole(sampleCartB);

	calculateCart(sampleCartC, globalSettings, productCatalog);
	showCartOnConsole(sampleCartC);

	calculateCart(sampleCartD, globalSettings, productCatalog);
	showCartOnConsole(sampleCartD);

	calculateCart(sampleCartE, globalSettings, productCatalog);
	showCartOnConsole(sampleCartE);

	calculateCart(sampleCartF, globalSettings, productCatalog);
	showCartOnConsole(sampleCartF);
	</script>



	<script id="jsbin-source-javascript" type="text/javascript">// Configuration values that are global to the store. These would need
	// some sort of a Magento dialog to allow the business team to maintain
	// them. Values are stored in cents to avoid JavaScript floating point
	// issues
	//
	// standardShippingRate
	// The amount of shipping that should be charged on a per item
	// basis unless the individual SKU has a special shipping charge
	// freeShippingThreshold
	// The amount of the sub-total of the cart of the items that do
	// not have special shipping charges that, once exceeded, will
	// result in a zero charge for shipping of the items that do not
	// have the special shipping charges

	var globalSettings = {
	standardShippingRate: 500,
	freeShippingThreshold: 12000
	};

	// Sample product catalog. Of course, in a real implementation, these
	// items would come from the product catalog database. And, the logic
	// around the price I'm sure has additional considerations. But, the
	// important new piece here is 'specialShippingCharge'. The product
	// inventory maintenance pages in the back-end would need to have a place
	// where the business team can set this 'specialShippingCharge' for
	// each item.
	//
	// sku
	// Unique identifier for the product catalog item
	// price
	// The integer price in cents (to avoid floating point problems in
	// JavaScipt) for one unit of the item
	// specialShippingCharge
	// If this amount is defined (or is not zero in strong typed
	// languages), then this amount defines the amount of shipping that
	// is always charged for this item.

	var productCatalog = {
	items: [
	{
	sku: "12345",
	price: 1000
	},{
	sku: "67890",
	price: 1500
	},{
	sku: "23456",
	price: 10500,
	specialShippingCharge: 7500
	},{
	sku: "78901",
	price: 12500
	},{
	sku: "34567",
	price: 750,
	specialShippingCharge: 500
	}
	]
	};

	// Various sample chopping carts


	// Empty cart

	var sampleCartA = {
	description: "Empty cart",
	items: []
	};

	// Cart containing no special shipping items

	var sampleCartB = {
	description: "Cart containing no special shipping items",
	items: [
	{
	sku:"12345",
	quantity: 3
	},{
	sku:"67890",
	quantity: 2
	},{
	sku:"34567",
	quantity: 2
	}
	]
	};

	// Cart containing no special shipping items but where the subtotal of
	// the items exceeds the free shipping threshold.

	var sampleCartC = {
	description: "Cart containing no special shipping items but where the subtotal of the items exceeds the free shipping threshold",
	items: [
	{
	sku:"12345",
	quantity: 30
	},{
	sku:"67890",
	quantity: 2
	}
	]
	};

	// Cart containing special shipping items

	var sampleCartD = {
	description: "Cart containing special shipping items",
	items: [
	{
	sku:"23456",
	quantity: 1
	},{
	sku:"34567",
	quantity: 2
	}
	]
	};

	// Cart containing a mix of regular and special shipping items

	var sampleCartE = {
	description: "Cart containing a mix of regular and special shipping items",
	items: [
	{
	sku:"12345",
	quantity: 3
	},{
	sku:"67890",
	quantity: 2
	},{
	sku:"34567",
	quantity: 2
	}
	]
	};

	// Cart containing a mix of regular and special shipping items where the
	// subtotal of the regular items exceeds the free shipping theshold.

	var sampleCartF = {
	description: "Cart containing a mix of regular and special shipping items where the subtotal of the regular items exceeds the free shipping theshold",
	items: [
	{
	sku:"12345",
	quantity:30
	},{
	sku:"67890",
	quantity:2
	},{
	sku:"23456",
	quantity: 2
	}
	]
	};


	// Helper function to left pad a string with a character to a width
	// Credit for this goes to: http://stackoverflow.com/a/9744576/959570

	function paddy(n, p, c) {
	var pad_char = typeof c !== 'undefined' ? c : '0';
	var pad = new Array(1 + p).join(pad_char);
	return (pad + n).slice(-pad.length);
	}

	// Helper function to add commas using U.S. format pattern (9,999,999)
	// Credit for this goes to: http://stackoverflow.com/a/2901298/3893444

	function addCommas(value) {
	return value.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
	}

	// A type-safe helper function to nicely format a string to a width.
	// Strings that are wider than the width are displayed as a width-wide
	// string of 'x'. If passed a non-string value, the value is returned
	// unaltered.

	function formatString(value, width) {
	if (typeof value !== 'string') {
	return value;
	}
	if (value.length > width) {
	return paddy('', width, 'x');
	} else {
	return paddy(value, width, ' ');
	}
	}

	// Helper function to nicely format currency based upon an integer
	// currency value where the least significant two digits represent cents
	// using U.S. format pattern ($ 9,999.99). Values that overflow the width
	// are displayed as a width-wide string of 'x'.

	function formatCurrency(value, width) {
	var dollars = Math.floor(value / 100);
	var cents = value % 100;
	var formatted = addCommas(dollars) + "." + paddy(cents, 2, "0");
	if (formatted.length + 1 > width) {
	return paddy('', width, 'x');
	} else {
	return '$' + paddy(formatted, width - 1, ' ');
	}
	}

	// Helper function to nicely format integers. Values that overflow the
	// width are displayed as a width-wide string of 'x'.

	function formatInteger(value, width) {
	if (value.length > width) {
	return paddy('', width, 'x');
	} else {
	return paddy(value, width, ' ');
	}
	}

	// Helper function to look up a SKU from the product catalog
	// Notes: This is a really stupid O(n) approach, but for this demo it
	// works fine

	function getSKU(sku, catalog) {
	var result = {},
	skuTemp,
	index,
	size;
	for (index = 0, size = catalog.items.length; index < size; index += 1) {
	skuTemp = catalog.items[index].sku;
	if (skuTemp !== undefined && skuTemp === sku) {
	return catalog.items[index];
	}
	}
	return undefined;
	}

	// Add unit prices to the items in the cart

	function addUnitPrices(cart, catalog) {
	var newItems = cart.items.map(function(item){
	var newItem = item,
	itemDetail = getSKU(item.sku, catalog),
	unitPrice;
	if (itemDetail === undefined \|\| itemDetail.price === undefined) {
	newItem.unitPrice = 0;
	} else {
	newItem.unitPrice = itemDetail.price;
	}
	return newItem;
	});
	return newItems;
	}


	// Calculate extended prices

	function extendPrices(cart) {
	var newItems = cart.items.map(function(item){
	var newItem = item;
	item.extendedPrice = item.unitPrice * item.quantity;
	return newItem;
	});
	return newItems;

	}

	// Calculate cart sub-total

	function calcSubtotal(cart) {
	cart.subtotal = 0;
	cart.items.forEach(function(item) {
	cart.subtotal += item.extendedPrice;
	});
	}

	// Add shipping costs to the cart

	function addShipping(cart, globals, catalog) {

	var regularShippingTotal = 0, // Accumulated regular shipping expenses
	specialShippingTotal = 0; // Accumulated special shipping expense

	// Spin through the items in the shopping cart evaluating the shipping
	// charge situation for each.

	cart.items.forEach(function(item) {

	// Look up the special shipping amount for the current cart item

	var specialShipping = getSKU(item.sku, catalog).specialShippingCharge;

	// If there is 'special shipping' amount for the item then add the
	// accumualted special shipping charges. Otherwise, add the global
	// regular shipping fee to the accumulated regular shipping charges.
	// Of course, both the above taking into account quanity.

	if (specialShipping !== undefined && specialShipping !== 0) {
	specialShippingTotal += specialShipping * item.quantity;
	} else {
	regularShippingTotal += globals.standardShippingRate * item.quantity;
	}
	});

	// Now that all items have been evaluated, if accumulated regular
	// shipping is over the global free shipping threshold then give
	// the customer free shipping.

	if (cart.subtotal > globals.freeShippingThreshold) {
	regularShippingTotal = 0;
	}

	// Final shipping amount equals regular plus special shipping

	cart.shipping = regularShippingTotal + specialShippingTotal;

	}

	// Calculate the cart total

	function calcTotal(cart) {
	cart.total = cart.subtotal + cart.shipping;
	}

	// Calculate the cart

	function calculateCart(cart, global, catalog) {
	addUnitPrices(cart, catalog);
	extendPrices(cart);
	calcSubtotal(cart);
	addShipping(cart, global, catalog);
	calcTotal(cart);
	}

	// Display the contents of a cart on the console

	function showCartOnConsole(cart) {
	console.log(cart.description);
	if (cart.items.length === 0) {
	console.log("The cart is empty");
	} else {
	cart.items.forEach(function(item) {
	console.log(
	formatString(item.sku, 6) + " " +
	formatCurrency(item.unitPrice, 10) + " " +
	formatInteger(item.quantity, 6) + " " +
	formatCurrency(item.extendedPrice, 10)
	);
	});
	console.log(
	formatString("Subtotal", 10) + " " +
	formatCurrency(cart.subtotal, 10)
	);
	console.log(
	formatString("Shipping", 10) + " " +
	formatCurrency(cart.shipping, 10)
	);
	console.log(
	formatString("Total", 10) + " " +
	formatCurrency(cart.total, 10)
	);
	}
	console.log("");
	}

	// Calculate test carts and show the results.

	calculateCart(sampleCartA, globalSettings, productCatalog);
	showCartOnConsole(sampleCartA);

	calculateCart(sampleCartB, globalSettings, productCatalog);
	showCartOnConsole(sampleCartB);

	calculateCart(sampleCartC, globalSettings, productCatalog);
	showCartOnConsole(sampleCartC);

	calculateCart(sampleCartD, globalSettings, productCatalog);
	showCartOnConsole(sampleCartD);

	calculateCart(sampleCartE, globalSettings, productCatalog);
	showCartOnConsole(sampleCartE);

	calculateCart(sampleCartF, globalSettings, productCatalog);
	showCartOnConsole(sampleCartF);</script></body>
	</html>