Choose a version:

useOptimisticCart

The useOptimisticCart takes an existing cart object, processes all pending cart actions, and locally mutates the cart with optimistic state. An optimistic cart makes cart actions immediately render in the browser while actions sync to the server. This increases the perceived performance of the application.

Anchor to useOptimisticCart
useOptimisticCart(
cart
)

Anchor to useOptimisticCart-parametersParameters

Anchor to cart cart: The cart object from context.cart.get() returned by a server loader.

Anchor to useOptimisticCart-returnsReturns

< = { lines?: { nodes: Array<{id: string; quantity: number; merchandise: {is: string}}>; }; }>

A new cart object augmented with optimistic state for lines and totalQuantity. Each cart line item that is optimistically added includes an isOptimistic property. Also if the cart has any optimistic state, a root property isOptimistic will be set to true.

DefaultCart

Promise<CartReturn | null> | CartReturn | null

CartReturn

Cart & {
  errors?: StorefrontApiErrors;
}

Cart

attributes

The cart's attributes.

{ __typename?: "Attribute"; key?: string; value?: string; }[]

buyerIdentity
The cart's buyer identity.
```
CartType['buyerIdentity']
```
checkoutUrl
The checkout URL for the cart, if the cart has been created in the Storefront API.
```
string
```
cost
The cost for the cart, including the subtotal, total, taxes, and duties.
```
CartType['cost']
```

discountCodes

The discount codes applied to the cart.

{ __typename?: "CartDiscountCode"; applicable?: boolean; code?: string; }[]

id
The cart's ID if it has been created through the Storefront API.
```
string
```

lines

The cart lines.

Array<CartLine | ComponentizableCartLine>

note
The cart's note.
```
string
```
totalQuantity
The total number of items in the cart, across all lines. If there are no lines, then the value is 0.
```
number
```

StorefrontApiErrors

JsonGraphQLError[] | undefined

JsonGraphQLError

extensions
Reserved for implementors to extend the protocol however they see fit, and hence there are no additional restrictions on its contents.
```
{ [key: string]: unknown; }
```
locations
If an error can be associated to a particular point in the requested GraphQL document, it should contain a list of locations.
```
{ line: number; column: number; }[]
```
message
```
string
```
name
```
string
```
path
If an error can be associated to a particular field in the GraphQL result, it _must_ contain an entry with the key `path` that details the path of the response field which experienced the error. This allows clients to identify whether a null result is intentional or caused by a runtime error.
```
(string | number)[]
```
stack
```
string
```

OptimisticCart

T extends undefined | null
  ? // This is the null/undefined case, where the cart has yet to be created.
    // But we still need to provide an optimistic cart object.
    {
      isOptimistic?: boolean;
      lines: {
        nodes: Array<OptimisticCartLine>;
      };
      totalQuantity?: number;
    } & Omit<PartialDeep<CartReturn>, 'lines'>
  : Omit<T, 'lines'> & {
      isOptimistic?: boolean;
      lines: {
        nodes: Array<OptimisticCartLine<T>>;
      };
      totalQuantity?: number;
    }

OptimisticCartLine

T extends LikeACart
  ? T['lines']['nodes'][number] & {isOptimistic?: boolean}
  : T & {isOptimistic?: boolean}

LikeACart

lines
```
{ nodes: unknown[]; }
```

Examples

import {Link} from 'react-router';

import {CartForm, useOptimisticCart} from '@shopify/hydrogen';

// Root loader returns the cart data

export async function loader({context}) {

return {

cart: context.cart.get(),

};

}

// The cart component renders each line item in the cart.

export function Cart({cart}) {

// `useOptimisticCart` adds optimistic line items to the cart.

// These line items are displayed in the cart until the server responds.

const optimisticCart = useOptimisticCart(cart);

if (!optimisticCart?.lines?.nodes?.length) return <p>Nothing in cart</p>;

return optimisticCart.lines.nodes.map((line) => (

{line.merchandise.product.title}

</Link>

<CartForm

route="/cart"

action={CartForm.ACTIONS.LinesRemove}

inputs={{lineIds: [line.id]}}

{/* Each line item has an `isOptimistic` property. Optimistic line items

should have actions disabled */}

Remove

</button>

</CartForm>

</div>

));

}

Examples

Example code

JavaScript

import {Link} from 'react-router';
import {CartForm, useOptimisticCart} from '@shopify/hydrogen';

// Root loader returns the cart data
export async function loader({context}) {
  return {
    cart: context.cart.get(),
  };
}

// The cart component renders each line item in the cart.
export function Cart({cart}) {
  // `useOptimisticCart` adds optimistic line items to the cart.
  // These line items are displayed in the cart until the server responds.
  const optimisticCart = useOptimisticCart(cart);

  if (!optimisticCart?.lines?.nodes?.length) return <p>Nothing in cart</p>;

  return optimisticCart.lines.nodes.map((line) => (
    <div key={line.id}>
      <Link to={`/products${line.merchandise.product.handle}`}>
        {line.merchandise.product.title}
      </Link>
      <CartForm
        route="/cart"
        action={CartForm.ACTIONS.LinesRemove}
        inputs={{lineIds: [line.id]}}
      >
        {/* Each line item has an `isOptimistic` property. Optimistic line items
        should have actions disabled */}
        <button type="submit" disabled={!!line.isOptimistic}>
          Remove
        </button>
      </CartForm>
    </div>
  ));
}

TypeScript

import {type LoaderFunctionArgs} from 'react-router';
import {Link} from 'react-router';
import {CartForm, useOptimisticCart} from '@shopify/hydrogen';
import type {Cart} from '@shopify/hydrogen/storefront-api-types';

// Root loader returns the cart data
export async function loader({context}: LoaderFunctionArgs) {
  return {
    cart: context.cart.get(),
  };
}

// The cart component renders each line item in the cart.
export function Cart({cart: originalCart}: {cart: Cart}) {
  // `useOptimisticCart` adds optimistic line items to the cart.
  // These line items are displayed in the cart until the server responds.
  const cart = useOptimisticCart(originalCart);
  if (!cart?.lines?.nodes?.length) return <p>Nothing in cart</p>;

  return cart.lines.nodes.map((line) => (
    <div key={line.id}>
      <Link to={`/products${line.merchandise.product.handle}`}>
        {line.merchandise.product.title}
      </Link>
      <CartForm
        route="/cart"
        action={CartForm.ACTIONS.LinesRemove}
        inputs={{lineIds: [line.id]}}
      >
        {/* Each line item has an `isOptimistic` property. Optimistic line items
        should have actions disabled */}
        <button type="submit" disabled={!!line.isOptimistic}>
          Remove
        </button>
      </CartForm>
    </div>
  ));
}

Anchor to RelatedRelated

CartForm

Was this page helpful?

Anchor to useOptimisticCartuseOptimisticCart(cartcart)