Medusa React

A React library providing a set of components, utilities, and hooks for interacting seamlessly with a Medusa backend and building custom React storefronts.

Installation

The library uses react-query as a solution for server-side state management and lists the library as a peer dependency.

In order to install the package, run the following

npm install medusa-react react-query @medusajs/medusa
# or
yarn add medusa-react react-query @medusajs/medusa

Quick Start

In order to use the hooks exposed by medusa-react, you will need to include the MedusaProvider somewhere up in your component tree. The MedusaProvider takes a baseUrl prop which should point to your Medusa server. Under the hood, medusa-react uses the medusa-js client library (built on top of axios) to interact with your server.

In addition, because medusa-react is built on top of react-query, you can pass an object representing react-query's QueryClientProvider props, which will be passed along by MedusaProvider.

// App.tsx

import * as React from "react"
import { QueryClient } from "react-query"
import { MedusaProvider } from "../src"
import MyStorefront from "./my-storefront"

// Your react-query's query client config
const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      refetchOnWindowFocus: false,
      staleTime: 30000,
      retry: 1,
    },
  },
})

const App = () => {
  return (
    <MedusaProvider
      queryClientProviderProps={{ client: queryClient }}
      baseUrl="http://localhost:9000"
    >
      <MyStorefront />
    </MedusaProvider>
  )
}

export default App

The hooks exposed by medusa-react fall into two main categories: queries and mutations.

Queries

Queries simply wrap around react-query's useQuery hook to fetch some data from your medusa server

// ./my-storefront.tsx
import * as React from "react"
import { useProducts } from "medusa-react"

const MyStorefront = () => {
  const { products, isLoading } = useProducts()

  return isLoading ? (
    <Spinner />
  ) : (
    products.map((product) => <Product product={product} />)
  )
}

In general, the queries will return everything react-query returns from useQuery except the data field, which will be flattened out. In addition, you can also access the HTTP response object returned from the medusa-js client including things like status, headers, etc.

So, in other words, we can express what the above query returns as the following:

import { UseQueryResult } from "react-query"

// This is what a Medusa server returns when you hit the GET /store/products endpoint
type ProductsResponse = {
  products: Product[]
  limit: number
  offset: number
}

// UseProductsQuery refers to what's returned by the useProducts hook
type UseProductsQuery = ProductsResponse &
  Omit<UseQueryResult, "data"> & {
    response: {
      status: number
      statusText: string
      headers: Record<string, string> & {
        "set-cookie"?: string[]
      }
      config: any
      request?: any
    }
  }

// More generally ...

type QueryReturnType = APIResponse &
  Omit<UseQueryResult, "data"> & {
    response: {
      status: number
      statusText: string
      headers: Record<string, string> & {
        "set-cookie"?: string[]
      }
      config: any
      request?: any
    }
  }

Mutations

Mutations wrap around react-query's useMutation to mutate data and perform server-side effects on your medusa server. If you are not entirely familiar with this idea of "mutations", creating a cart would be a mutation because it creates a cart in your server (and database). Mutations also have to be invoked imperatively, meaning that calling for the mutation to take action, you will have to call a mutate() function returned from mutation hooks.

import * as React from "react"
import { useCreateCart } from "medusa-react"

const CreateCartButton = () => {
  const createCart = useCreateCart()
  const handleClick = () => {
    createCart.mutate({}) // create an empty cart
  }

  return (
    <Button isLoading={createCart.isLoading} onClick={handleClick}>
      Create cart
    </Button>
  )
}

The mutation hooks will return exactly what react-query's useMutation returns. In addition, the options you pass in to the hooks will be passed along to useMutation.

Utilities

A set of utility functions are also exposed from the library to make your life easier when dealing with displaying money amounts

formatVariantPrice()

• formatVariantPrice(params: FormatVariantPriceParams): string

type FormatVariantPriceParams = {
  variant: ProductVariantInfo
  region: RegionInfo
  includeTaxes?: boolean
  minimumFractionDigits?: number
  maximumFractionDigits?: number
  locale?: string
}

type ProductVariantInfo = Pick<ProductVariant, "prices">

type RegionInfo = {
  currency_code: string
  tax_code: string
  tax_rate: number
}

Given a variant and region, will return a string representing the localized amount (i.e: $19.50)

The behavior of minimumFractionDigits and maximumFractionDigits is the same as the one explained by MDN here. In fact, in order to convert the decimal amount, we use the browser's Intl.NumberFormat method.

computeVariantPrice()

• computeVariantPrice(params: ComputeVariantPriceParams): number

type ComputeVariantPriceParams = {
  variant: ProductVariantInfo
  region: RegionInfo
  includeTaxes?: boolean
}

Determines a variant's price based on the region provided. Returns a decimal number representing the amount.

formatAmount()

• formatAmount(params: FormatAmountParams): string

type FormatAmountParams = {
  amount: number
  region: RegionInfo
  includeTaxes?: boolean
  minimumFractionDigits?: number
  maximumFractionDigits?: number
  locale?: string
}

Returns a localized string based on the input params representing the amount (i.e: "$10.99").

computeAmount()

• computeAmount(params: ComputeAmountParams): number

type ComputeAmountParams = {
  amount: number
  region: RegionInfo
  includeTaxes?: boolean
}

Takes an integer amount, a region, and includeTaxes boolean. Returns a decimal amount including (or excluding) taxes.

Context Providers (Experimental)

In order to make building custom storefronts easier, we also expose a SessionCartProvider and a CartProvider . At first, the two sound very similar to each other, however, the main distinction between the two is that the SessionCartProvider never interacts with your medusa server.

The main goal behind the provider is to manage the state related to your users' cart experience. In other words, the provider keeps track of the items users add to their cart and help you interact with those items through a set of helpful methods like addItem, updateQuantity, removeItem , etc.

On the other hand the CartProvider makes use of some of the hooks already exposed by medusa-react to help you create a cart (on the medusa backend), start the checkout flow, authorize payment sessions, etc. It also manages one single global piece of state which represents a cart, exactly like the one created on your medusa backend.

You can think of a sessionCart as a purely client-side lightweight cart, in other words, just a javascript object living in your browser, whereas cart is the entity which you have stored in your database.

SessionCart

The first step to using the SessionCartProvider is by inserting it somewhere up in your component tree.

// App.tsx

import * as React from "react"
import { QueryClient } from "react-query"
import { MedusaProvider, SessionCartProvider } from "medusa-react"
import MyStorefront from "./my-storefront"

// Your react-query's query client config
const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      refetchOnWindowFocus: false,
      staleTime: 30000,
      retry: 1,
    },
  },
})

const App = () => {
  return (
    <MedusaProvider
      queryClientProviderProps={{ client: queryClient }}
      baseUrl="http://localhost:9000"
    >
      <SessionCartProvider>
        <MyStorefront />
      </SessionCartProvider>
    </MedusaProvider>
  )
}

export default App

Cart

// App.tsx

import * as React from "react"
import { QueryClient } from "react-query"
import { MedusaProvider, CartProvider } from "medusa-react"
import MyStorefront from "./my-storefront"

// Your react-query's query client config
const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      refetchOnWindowFocus: false,
      staleTime: 30000,
      retry: 1,
    },
  },
})

const App = () => {
  return (
    <MedusaProvider
      queryClientProviderProps={{ client: queryClient }}
      baseUrl="http://localhost:9000"
    >
      <CartProvider>
        <MyStorefront />
      </CartProvider>
    </MedusaProvider>
  )
}

export default App