# Composables

While API Client is a data layer for the application composables are the business logic part based on Vue.js Composition API (opens new window). This package contains the following Composition API functions responsible for interacting with specific parts of eCommerce platform logic:

  • useProduct to fetch, filter and sort products
  • useCategory to fetch categories
  • useCart to manage basket
  • useUser to manage authorization and user profile
    • useUserOrder (subcomposable to useUser) to manage user orders that has already been placed
    • useUserAddresses (subcomposable to useUser) to manage user shipping addresses
  • useCheckout to manage order processing

Each of this function works independently and combined they are covering all the logic of your eCommerce platform.

Every composable is exposing more or less following properties:

  • Main data object - a single, readonly object that the rest of the composition function interacts with or depends on. For example in useProduct it's a products object that search() function interacts with.
  • Main function that interacts with data object which usually calls the API and updates the main data object, For example in useProduct and useCategory it's a search method, in useCart it's a load() method etc.
  • Supportive data objects which are depending directly on indirectly on the main data object, for example, loading, error or isAuthenticated from useUser that is depending on user object.

Let's see an example of how Vue Storefront Composable could look like. This is how you can perform a product search:

At the moment of invoking a search method theloading property value changes to true. Once the api call is done products object is populated with the result and loading becomes false again.

# Getters

TIP

Usage of getters is coompletely optional. Use them where it makes sense to you.

Sometimes its hard to extract certain subproperties from complex data objects like products or categories and display them in the UI in a simple way. This is the reason why we introduced getters. Every getter is a simple function you can use to extract certain subproperties from specific objects. Every composable has its corresponding getter functions.

import { useProduct, productGetters } from '@vue-storefront/shopify'

const { products, search } = useProduct()

search({ id: '12345' })

const attributes = computed(() => productGetters.getAttributes(product.value[0]))

Writing backend-agnostic code

In many cases using getters can save you time and contribute to cleaner code but there is one more thing about getters that makes them really useful. They're always returning agnostic data formats. No matter which platform we're using productGetters.getAttributes() will always return the data in a same, UI-friendly format.

Because interfaces for composables and getters are the same for every platform the above code from above example will work exactly the each one of them. Because of that you can use getters to keep your frontend code agnostic regarding eCommerce platform. This approach can be really useful when you're considering a migration to different platform in the near future