Refetching Queries

Although Apollo Client allows you to make local modifications to previously received GraphQL data by updating the cache, sometimes the easiest way to update your client-side GraphQL data is to refetch it from the server.

In principle, you could refetch every active query after any client-side update, but you can save time and network bandwidth by refetching queries more selectively, taking advantage of InMemoryCache to determine which watched queries may have been invalidated by recent cache updates.

These two approaches (local updates and refetching) work well together: if your application displays the results of local cache modifications immediately, you can use refetching in the background to obtain the very latest data from the server, rerendering the UI only if there are differences between local data and refetched data.

Refetching is especially common after a mutation, so client.mutate accepts options like refetchQueries and onQueryUpdated to specify which queries should be refetched, and how. However, the tools of selective refetching are available even if you are not performing a mutation, in the form of the client.refetchQueries method.

client.refetchQueries

Refetch options

interface RefetchQueriesOptions<
  TCache extends ApolloCache<any>,
  TResult = Promise<ApolloQueryResult<any>>,
> {
  updateCache?: (cache: TCache) => void;
  include?: Array<string | DocumentNode> | "all" | "active";
  onQueryUpdated?: (
    observableQuery: ObservableQuery<any>,
    diff: Cache.DiffResult<any>,
    lastDiff: Cache.DiffResult<any> | undefined,
  ) => boolean | TResult;
  optimistic?: boolean;
}

Refetch results

The client.refetchQueries method collects the TResult results returned by onQueryUpdated, defaulting to TResult = Promise<ApolloQueryResult<any>> if onQueryUpdated is not provided, and combines the results into a single Promise<TResolved[]> using Promise.all(results).

Thanks to the Promise-unwrapping behavior of Promise.all, this TResolved type will often be the same type as TResult, except when TResult is a PromiseLike<TResolved> or a boolean.

The returned Promise object has two other useful properties:

These two arrays parallel each other: they have the same length, and results[i] is the result produced by onQueryUpdated when called with the ObservableQuery found at queries[i], for any index i.

Refetch recipes

To refetch a specific query by name, use the include option by itself:

await client.refetchQueries({
  include: ["SomeQueryName"],
});

The include option can also refetch a specific query using its DocumentNode:

await client.refetchQueries({
  include: [SOME_QUERY],
});

To refetch all active queries, pass the "active" shorthand for include:

await client.refetchQueries({
  include: "active",
});

To refetch all queries managed by Apollo Client, even those with no observers, or whose components are currently unmounted, pass "all" for include:

await client.refetchQueries({
  include: "all", // Consider using "active" instead!
});

Alternatively, you can refetch queries affected by cache updates performed in the updateCache callback:

await client.refetchQueries({
  updateCache(cache) {
    cache.evict({ fieldName: "someRootField" });
  },
});

This will refetch any queries that depend on Query.someRootField, without requiring you to know in advance which queries might be included. Any combination of cache operations (writeQuery, writeFragment, modify, evict, etc.) is allowed within updateCache. Updates performed by updateCache persist in the cache by default, but you can choose to perform them in a temporary optimistic layer instead, if you want them to be discarded immediately after client.refetchQueries is done observing them, leaving the cache unchanged:

await client.refetchQueries({
  updateCache(cache) {
    cache.evict({ fieldName: "someRootField" });
  },

  // Evict Query.someRootField only temporarily, in an optimistic layer.
  optimistic: true,
});

Another way of updating the cache without changing cache data is to use cache.modify and its INVALIDATE sentinel object:

await client.refetchQueries({
  updateCache(cache) {
    cache.modify({
      fields: {
        someRootField(value, { INVALIDATE }) {
          // Update queries that involve Query.someRootField, without actually
          // changing its value in the cache.
          return INVALIDATE;
        },
      },
    });
  },
});

Before client.refetchQueries was introduced, the INVALIDATE sentinel was not very useful, since invalidated queries with fetchPolicy: "cache-first" would typically re-read unchanged results, and therefore decide not to perform a network request. The client.refetchQueries method makes this invalidation system more accessible to application code, so you can control the refetching behavior of invalidated queries.

In all of the examples above, whether we use include or updateCache, client.refetchQueries will refetch the affected queries from the network and include the resulting Promise<ApolloQueryResult<any>> results in the Promise<TResolved[]> returned by client.refetchQueries. If a single query happens to be included both by include and by updateCache, that query will be refetched only once. In other words, the include option is a good way to make sure certain queries are always included, no matter which queries are included by updateCache.

In development, you will probably want to make sure the appropriate queries are getting refetched, rather than blindly refetching them. To intercept each query before refetching, you can specify an onQueryUpdated callback:

const results = await client.refetchQueries({
  updateCache(cache) {
    cache.evict({ fieldName: "someRootField" });
  },

  onQueryUpdated(observableQuery) {
    // Logging and/or debugger breakpoints can be useful in development to
    // understand what client.refetchQueries is doing.
    console.log(`Examining ObservableQuery ${observableQuery.queryName}`);
    debugger;

    // Proceed with the default refetching behavior, as if onQueryUpdated
    // was not provided.
    return true;
  },
});

results.forEach(result => {
  // These results will be ApolloQueryResult<any> objects, after all
  // results have been refetched from the network.
});

Notice how adding onQueryUpdated in this example did not change the refetching behavior of client.refetchQueries, allowing us to use onQueryUpdated purely for diagnostic or debugging purposes.

If you want to skip certain queries that would otherwise be included, return false from onQueryUpdated:

await client.refetchQueries({
  updateCache(cache) {
    cache.evict({ fieldName: "someRootField" });
  },

  onQueryUpdated(observableQuery) {
    console.log(`Examining ObservableQuery ${
      observableQuery.queryName
    } whose latest result is ${JSON.stringify(result)} which is ${
      complete ? "complete" : "incomplete"
    }`);

    if (shouldIgnoreQuery(observableQuery)) {
      return false;
    }

    // Refetch the query unconditionally from the network.
    return true;
  },
});

In case the ObservableQuery does not provide enough information, you can also examine the latest result for the query, along with information about its completeness and missing fields, using the Cache.DiffResult object passed as the second parameter to onQueryUpdated:

await client.refetchQueries({
  updateCache(cache) {
    cache.evict({ fieldName: "someRootField" });
  },

  onQueryUpdated(observableQuery, { complete, result, missing }) {
    if (shouldIgnoreQuery(observableQuery)) {
      return false;
    }

    if (complete) {
      // Update the query according to its chosen FetchPolicy, rather than
      // refetching it unconditionally from the network.
      return observableQuery.reobserve();
    }

    // Refetch the query unconditionally from the network.
    return true;
  },
});

Because onQueryUpdated has the ability to filter queries dynamically, it also pairs well with the bulk include options mentioned above:

await client.refetchQueries({
  // Include all active queries by default, which may be ill-advised unless
  // you also use onQueryUpdated to filter those queries.
  include: "active";

  // Called once for every active query, allowing dynamic filtering:
  onQueryUpdated(observableQuery) {
    return !shouldIngoreQuery(observableQuery);
  },
});

In the examples above we await client.refetchQueries(...) to find out the final ApolloQueryResult<any> results for all the refetched queries. This combined promise is created with Promise.all, so a single failure will reject the entire Promise<TResolved[]>, potentially hiding other successful results. If this is a problem, you can use the queries and results arrays returned by client.refetchQueries instead of (or in addition to) awaiting the Promise:

const { queries, results } = client.refetchQueries({
  // Specific client.refetchQueries options are not relevant to this example.
});

const finalResults = await Promise.all(
  results.map((result, i) => {
    return Promise.resolve(result).catch(error => {
      console.error(`Error refetching query ${queries[i].queryName}: ${error}`);
      return null; // Silence this Promise rejection.
    });
  })
});

In the future, just as additional input options may be added to the client.refetchQueries method, additional properties may be added to its result object, supplementing its Promise-related properties and the queries and results arrays.

If you discover that some specific additional client.refetchQueries input options or result properties would be useful, please feel free to open an issue or start a discussion explaining your use case(s).

Relationship to client.mutate options

For refetching after a mutation, the client.mutate method supports options similar to client.refetchQueries, which you should use instead of client.refetchQueries, because it's important for refetching logic to happen at specific times during the mutation process.

For historical reasons, the client.mutate options have slightly different names from the new client.refetchQueries options, but their internal implementation is substantially the same, so you can translate between them using the following table: