Add optional metadata to StorePostCartsCartLineItemsItemReq

[erikengervall]

Hey all 👋🏼

I recently started using Medusajs (looks great so far!) and was hoping it'd be possible to add metadata as an optional field to StorePostCartsCartLineItemsItemReq.

The creation endpoint accepts metadata:

medusa/packages/medusa/src/api/routes/store/carts/create-line-item/index.ts

Lines 161 to 170 in 274056a

	export class StorePostCartsCartLineItemsReq {
	@IsString()
	variant_id: string
	@IsInt()
	quantity: number
	@IsOptional()
	metadata?: Record<string, unknown> | undefined
	}

...but the update endpoint doesn't:

medusa/packages/medusa/src/api/routes/store/carts/update-line-item.ts

Lines 128 to 131 in 274056a

	export class StorePostCartsCartLineItemsItemReq {
	@IsInt()
	quantity: number
	}

This is the corresponding hook:

medusa/packages/medusa-react/src/hooks/store/line-items/mutations.ts

Lines 25 to 42 in 274056a

	export const useUpdateLineItem = (
	cartId: string,
	options?: UseMutationOptions<
	StoreCartsRes,
	Error,
	StorePostCartsCartLineItemsItemReq & { lineId: string }
	>
	) => {
	const { client } = useMedusa()
	return useMutation(
	({
	lineId,
	...data
	}: StorePostCartsCartLineItemsItemReq & { lineId: string }) =>
	client.carts.lineItems.update(cartId, lineId, data),
	options
	)
	}

---

We've got a use case where we'd like to enrich line items' metadata field just before entering the checkout flow. Without the addition of metadata to StorePostCartsCartLineItemsItemReq, the options I see are

• Creating a custom endpoint that's almost identical to StorePostCartsCartLineItemsItemReq but that accepts metadata
  • Although this would work just fine in the short term, we would effectively opt out of future updates to this endpoint, which I would prefer not to do.
• Call deleteItem followed by addItem as addItem accepts metadata.
  • This is quite hacky and it also causes the UI to render the Empty Cart page for a brief moment.

---

Thanks!

Edit: I went ahead and created a PR for this feature.