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shoppy.cart.update(lineId, quantity)
shoppy.cart.update(lines)
Updates the quantity of one or more items in the cart.

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Parameters

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Single item

ParamTypeRequiredDescription
lineIdstringYesCart line ID
quantitynumberYesNew quantity

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Multiple items

ParamTypeRequiredDescription
linesCartLineUpdateInput[]YesArray of updates

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Returns

Promise<ShopifyCart>

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Examples

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Update single item

const lines = shoppy.cart.lines()
await shoppy.cart.update(lines[0].id, 5)

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Update multiple items

const lines = shoppy.cart.lines()

await shoppy.cart.update([
    { id: lines[0].id, quantity: 2 },
    { id: lines[1].id, quantity: 4 }
])

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Quantity selector

document
    .querySelector('.quantity-input')
    .addEventListener('change', async (e) => {
        const lineId = e.target.dataset.lineId
        const quantity = parseInt(e.target.value)

        if (quantity > 0) {
            await shoppy.cart.update(lineId, quantity)
        }
    })

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Increment/decrement buttons

async function updateQuantity(lineId, delta) {
    const line = shoppy.cart.lines().find((l) => l.id === lineId)
    const newQuantity = line.quantity + delta

    if (newQuantity > 0) {
        await shoppy.cart.update(lineId, newQuantity)
    } else {
        await shoppy.cart.remove(lineId)
    }
}
Setting quantity to 0 will not remove the item. Use .remove() instead.