use
utility
The 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-parametersParameters
Anchor to cart
cart
The cart object from context.cart.get() returned by a server loader.
< = {
lines?: {
nodes: Array<{id: string; quantity: number; merchandise: {is: string}}>;
};
}>
A new cart object augmented with optimistic state for lines and . Each cart line item that is optimistically added includes an property. Also if the cart has any optimistic state, a root property will be set to true.
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Example code
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>
));
}
