useMany

useMany is an extended version of TanStack Query's useQuery. It supports all the features of useQuery and adds some extra features.

• It uses the getMany method as the query function from the dataProvider which is passed to <Refine>.

• It uses a query key to cache the data. The query key is generated from the provided properties. You can see the query key by using the TanStack Query devtools.

It is useful when you want to fetch multiple records from the API. It will return the data and some functions to control the query.

caution

If your data provider does not have a getMany method, useMany will use the getOne method instead. It is not recommended, because it will make requests one by one for each id. It is better to implement the getMany method in the data provider.

Basic Usage

The useMany hook expects a resource and ids property. It will be passed to the getMany method from the dataProvider as a parameter.

When these properties are changed, the useMany hook will trigger a new request.

http://localhost:3000

import { useState } from "react";
import { useMany, HttpError } from "@refinedev/core";

interface IProduct {
    id: number;
    name: string;
    material: string;
}

const ProductList: React.FC = () => {
    const [ids, setIds] = useState([1, 2, 3]);

    const { data, isLoading, isError } = useMany<IProduct, HttpError>({
        resource: "products",
        ids,
    });

    const products = data?.data ?? [];

    if (isLoading) {
        return <div>Loading...</div>;
    }

    if (isError) {
        return <div>Something went wrong!</div>;
    }

    return (
        <div>
            {products.map((product) => (
                <ul key={product.id}>
                    <li key={product.id}>
                        {product.id} - {product.name}{" "}
                        <button
                            onClick={() =>
                                setIds((prev) =>
                                    prev.filter((id) => id !== product.id),
                                )
                            }
                        >
                            remove
                        </button>
                    </li>
                </ul>
            ))}

            <button
                onClick={() => {
                    setIds((prev) => [
                        ...prev,
                        Math.floor(Math.random() * 1000) + 1,
                    ]);
                }}
            >
                Add new product
            </button>
        </div>
    );
};

Realtime Updates

This feature is only available if you use a Live Provider.

When the useMany hook is mounted, it will call the subscribe method from the liveProvider with some parameters such as channel, resource etc. It is useful when you want to subscribe to live updates.

Refer to the liveProvider documentation for more information &#8594

Properties

resource

required

It will be passed to the getMany method from the dataProvider as a parameter. The parameter is usually used as an API endpoint path. It all depends on how to handle the resource in the getMany method. See the creating a data provider section for an example of how resources are handled.

useMany({
    resource: "categories",
});

ids

required

It will be passed to the getMany method from the dataProvider as a parameter. It is used to determine which records to fetch.

useMany({
    ids: [1, 2, 3],
});

dataProviderName

If there is more than one dataProvider, you can specify which one to use by passing the dataProviderName prop. It is useful when you have a different data provider for different resources.

useMany({
    dataProviderName: "second-data-provider",
});

queryOptions

queryOptions is used to pass additional options to the useQuery hook. It is useful when you want to pass additional options to the useQuery hook.

Refer to the useQuery documentation for more information &#8594

useMany({
    queryOptions: {
        retry: 3,
        enabled: false,
    },
});

meta

meta is used following two purposes:

• To pass additional information to data provider methods.
• Generate GraphQL queries using plain JavaScript Objects (JSON). Please refer GraphQL for more information.

In the following example, we pass the headers property in the meta object to the create method. With similar logic, you can pass any properties to specifically handle the data provider methods.

import { stringify } from "query-string";

useMany({
    meta: {
        headers: { "x-meta-data": "true" },
    },
});

const myDataProvider = {
    //...
    getMany: async ({
        resource,
        ids,
        meta,
    }) => {
        const headers = meta?.headers ?? {};
        const url = `${apiUrl}/${resource}?${stringify({ id: ids })}`;

        //...
        //...

        const { data } = await httpClient.get(`${url}`, { headers });

        return {
            data,
        };
    },
    //...
};

successNotification

NotificationProvider is required for this prop to work.

After data is fetched successfully, useMany can call open function from NotificationProvider to show a success notification. With this prop, you can customize the success notification.

useMany({
    successNotification: (data, ids, resource) => {
        return {
            message: `${data.title} Successfully fetched.`,
            description: "Success with no errors",
            type: "success",
        };
    },
});

errorNotification

NotificationProvider is required for this prop to work.

After data fetching is failed, useMany will call the open function from NotificationProvider to show an error notification. With this prop, you can customize the error notification.

useMany({
    errorNotification: (data, ids, resource) => {
        return {
            message: `Something went wrong when getting ${data.id}`,
            description: "Error",
            type: "error",
        };
    },
});

liveMode

LiveProvider is required for this prop to work.

Determines whether to update data automatically ("auto") or not ("manual") if a related live event is received. It can be used to update and show data in Realtime throughout your app. For more information about live mode, please check the Live / Realtime page.

useMany({
    liveMode: "auto",
});

onLiveEvent

LiveProvider is required for this prop to work.

The callback function is executed when new events from a subscription have arrived.

useMany({
    onLiveEvent: (event) => {
        console.log(event);
    },
});

liveParams

LiveProvider is required for this prop to work.

Params to pass to liveProvider's subscribe method.

Return Values

Returns an object with TanStack Query's useQuery return values.

Refer to the useQuery documentation for more information &#8594

API

Properties

Type Parameters

Property	Desription	Type	Default
TQueryFnData	Result data returned by the query function. Extends BaseRecord	BaseRecord	BaseRecord
TError	Custom error object that extends HttpError	HttpError	HttpError
TData	Result data returned by the select function. Extends BaseRecord. If not specified, the value of TQueryFnData will be used as the default value.	BaseRecord	TQueryFnData

Return values

Description	Type
Result of the TanStack Query's useQuery	QueryObserverResult<{ data: TData[]; }>