commerce/packages/saleor/src/cart/use-add-item.tsx

import { useCallback } from 'react'
import type { MutationHook } from '@commerce/utils/types'
import { CommerceError } from '@commerce/utils/errors'
import useAddItem, { UseAddItem } from '@commerce/cart/use-add-item'
import useCart from './use-cart'

import * as mutation from '../utils/mutations'

import { getCheckoutId, checkoutToCart } from '../utils'

import { Mutation, MutationCheckoutLinesAddArgs } from '../schema'
import { AddItemHook } from '@commerce/types/cart'

export default useAddItem as UseAddItem<typeof handler>

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

    const { checkoutLinesAdd } = await fetch<Mutation, MutationCheckoutLinesAddArgs>({
      ...options,
      variables: {
        checkoutId: getCheckoutId().checkoutId,
        lineItems: [
          {
            variantId: item.variantId,
            quantity: item.quantity ?? 1,
          },
        ],
      },
    })

    return checkoutToCart(checkoutLinesAdd)
  },
  useHook:
    ({ fetch }) =>
    () => {
      const { mutate } = useCart()

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