# Pricing & Availability

### Item Prices and Availability

Pricing and availability for individual items and services are displayed in the Spectrum UI, with data provided by the `spectrumItemPricesAndAvailabilityCallback` function. This function has one argument in the signature: `skus`.

```javascript
window.spectrumItemPricesAndAvailabilityCallback = function(itemsBySkuOrName) { 
  // itemsBySkuOrName: array of strings that can refer to SKUs, parts, or decoration services
}
```

This callback should return a promise that resolves to an array of objects with the following properties:

```javascript
[
  {
    sku: 'exampleSku',
    name: 'Example',
    type: 'baseProduct',
    price: 99.99,
    listPrice: null,     // nullable list price to distinguish from sale price
    isoCurrency: 'USD',  // must be a valid ISO 4217 currency code
    inStock: true,
    options: null        // nullable options object with string values
  }
]
```

### Total Price

Displaying the total price for a customized product at runtime can be supported by exposing a global `spectrumTotalPriceCallback` function. This ensures that ecommerce systems are the single source of truth pricing calculations and ensures that discounts, upcharges are accurate and consistent with how they appear at checkout.

```javascript
window.spectrumTotalPriceCallback = function(items) {
  // items[n].sku: string | null
  // items[n].name: string | null
  // items[n].quantity: number (unsigned int)
}
```

This callback should return a promise that resolves into an object with the following properties:

```javascript
{
  price: 999.99,
  isoCurrency: 'USD',  // must be a valid ISO 4217 currency code
  options: null        // nullable options object with string values
}
```