commerce/framework/vendure/cart/use-add-item.tsx

import { Cart, CartItemBody } from '@commerce/types'
import useAddItem, { UseAddItem } from '@commerce/cart/use-add-item'
import { CommerceError } from '@commerce/utils/errors'
import { MutationHook } from '@commerce/utils/types'
import { useCallback } from 'react'
import useCart from './use-cart'
import { cartFragment } from '../api/fragments/cart'
import { AddItemToOrderMutation } from '../schema'
import { normalizeCart } from '../lib/normalize'

export const addItemToOrderMutation = /* GraphQL */ `
  mutation addItemToOrder($variantId: ID!, $quantity: Int!) {
    addItemToOrder(productVariantId: $variantId, quantity: $quantity) {
      __typename
      ...Cart
      ... on ErrorResult {
        errorCode
        message
      }
    }
  }
  ${cartFragment}
`

export default useAddItem as UseAddItem<typeof handler>

export const handler: MutationHook<Cart, {}, CartItemBody> = {
  fetchOptions: {
    query: addItemToOrderMutation,
  },
  async fetcher({ input, options, fetch }) {
    if (
      input.quantity &&
      (!Number.isInteger(input.quantity) || input.quantity! < 1)
    ) {
      throw new CommerceError({
        message: 'The item quantity has to be a valid integer greater than 0',
      })
    }

    const { addItemToOrder } = await fetch<AddItemToOrderMutation>({
      ...options,
      variables: {
        quantity: input.quantity || 1,
        variantId: input.variantId,
      },
    })

    if (addItemToOrder.__typename === 'Order') {
      return normalizeCart(addItemToOrder)
    }
    throw new CommerceError(addItemToOrder)
  },
  useHook: ({ fetch }) => () => {
    const { mutate } = useCart()

    return useCallback(
      async function addItem(input) {
        const data = await fetch({ input })
        await mutate(data, false)
        return data
      },
      [fetch, mutate]
    )
  },
}