# useMetafield

Returns a single filtered `Metafield` or `undefined`.

## 

### UseMetafieldGeneratedType

Returns a single filtered `Metafield` or `undefined`.

#### Returns: Metafield | undefined

#### Params:

- filters: MetafieldFilter
export function useMetafield(filters: MetafieldFilter): Metafield | undefined {
  const {namespace, key} = filters;

  if (!namespace || !key) {
    throw new CheckoutUIExtensionError(
      'You must pass in both a namespace and key',
    );
  }

  const metafields = useMetafields({namespace, key});

  return metafields.length ? metafields[0] : undefined;
}


### MetafieldFilter

### namespace

value: `string`


### key

value: `string`


### Metafield

Metadata associated with the checkout.

### key

value: `string`

The name of the metafield. It must be between 3 and 30 characters in
length (inclusive).

### namespace

value: `string`

A container for a set of metafields. You need to define a custom
namespace for your metafields to distinguish them from the metafields
used by other apps. This must be between 2 and 20 characters in length (inclusive).

### value

value: `string | number`

The information to be stored as metadata.

### valueType

value: `"string" | "integer" | "json_string"`

The metafield’s information type.

## Related

- [StandardApi](https://shopify.dev/docs/api/checkout-ui-extensions/apis/standardapi)
- [CheckoutApi](https://shopify.dev/docs/api/checkout-ui-extensions/apis/checkoutapi)
- [OrderStatusApi](https://shopify.dev/docs/api/checkout-ui-extensions/apis/orderstatusapi)
- [CartLineItemApi](https://shopify.dev/docs/api/checkout-ui-extensions/apis/cartlineitemapi)
- [PickupPointListApi](https://shopify.dev/docs/api/checkout-ui-extensions/apis/pickuppointlistapi)
- [PickupLocationListApi](https://shopify.dev/docs/api/checkout-ui-extensions/apis/pickuplocationlistapi)
- [ShippingOptionItemApi](https://shopify.dev/docs/api/checkout-ui-extensions/apis/shippingoptionitemapi)
- [ExtensionTargets](https://shopify.dev/docs/api/checkout-ui-extensions/apis/extensiontargets)