Migrating to Apollo Client 3.0

This article walks you through migrating your application to Apollo Client 3.0 from previous versions of Apollo Client.

To illustrate the migration process, we've also made this video that uses the example app from our full-stack tutorial as a starting point, updating it from Apollo client 2.6 to 3.0:

What’s new in 3.0

Apollo Client is now distributed as the @apollo/client package (previous versions are distributed as apollo-client).
The @apollo/client package includes both React hooks and GraphQL request handling, which previously required installing separate packages.
Apollo Client’s cache (InMemoryCache) is more flexible and performant. It now supports garbage collection, storage of both normalized and non-normalized data, and the customization of cached data with new TypePolicy and FieldPolicy APIs.
The update also includes numerous bug fixes and optimizations, as described in the changelog.

Installation

WARNING: Apollo Client 3.0 is a major-version release that includes breaking changes. If you are updating an existing application to use Apollo Client 3.0, please see the changelog for details about these changes.

Install Apollo Client 3.0 with the following command:

npm install @apollo/client

If you’re installing Apollo Client 3.0 in a project that already uses an earlier version, follow the instructions in each section of Updating imports that applies to a library you are currently using.

Updating imports

The @apollo/client library includes functionality that previously required installing additional packages. As part of migrating to Apollo Client 3.0, follow the instructions below for each library your application currently uses.

@apollo/react-hoc and @apollo/react-components

React Apollo HOC and component functionality is now included in the @apollo/client package:

import { Query, Mutation, Subscription } from '@apollo/client/react/components';
import { graphql } from '@apollo/client/react/hoc';

As part of migrating, we recommend removing all @apollo/react-hoc and @apollo/react-components dependencies.

@apollo/react-hooks

All @apollo/react-hooks functionality is included in the @apollo/client package. For example:

import { ApolloProvider, useQuery, useApolloClient } from '@apollo/client'

As part of migrating, we recommend removing all @apollo/react-hooks dependencies.

@apollo/react-ssr

React Apollo’s SSR utilities (like getDataFromTree, getMarkupFromTree, and renderToStringWithData) are included in the @apollo/client package. Access them via @apollo/client/react/ssr:

import { renderToStringWithData } from '@apollo/client/react/ssr';

As part of migrating, we recommend removing all @apollo/react-ssr dependencies.

@apollo/react-testing

React Apollo’s testing utilities (like MockedProvider) are included in the @apollo/client package. Access them via @apollo/client/testing:

import { MockedProvider } from '@apollo/client/testing';

As part of migrating, we recommend removing all @apollo/react-testing dependencies.

apollo-boost

The Apollo Boost project is now retired, because Apollo Client 3.0 provides a similarly straightforward setup. We recommend removing all apollo-boost dependencies and modifying your ApolloClient constructor as needed.

apollo-client

With Apollo Client 3.0, the apollo-client package is retired in favor of @apollo/client. As part of migrating, remove all apollo-client dependencies.

apollo-link and apollo-link-http

All apollo-link, apollo-link-http, and apollo-link-http-common functionality is included in the @apollo/client package. For example:

import { ApolloLink, HttpLink, from, split, execute } from '@apollo/client';

As part of migrating, we recommend removing all apollo-link, apollo-link-http, and apollo-link-http-common dependencies.

If you want to configure your own link chain, the ApolloClient constructor still accepts a link option. Otherwise, the ApolloClient constructor now also supports uri, headers, and credentials options. For example:

const client = new ApolloClient({
  cache,
  uri: 'http://localhost:4000/graphql',
  headers: {
    authorization: localStorage.getItem('token') || '',
    'client-name': 'Space Explorer [web]',
    'client-version': '1.0.0',
  },
  ...
});

These options are passed into a new HttpLink instance behind the scenes, which ApolloClient is then configured to use.

apollo-link-*

The separate apollo-link-* packages, that were previously maintained in the https://github.com/apollographql/apollo-link repo, have been merged into the Apollo Client project. These links now have their own nested @apollo/client entry points. Imports should be updated as follows:

apollo-link-batch is now @apollo/client/link/batch
apollo-link-batch-http is now @apollo/client/link/batch-http
apollo-link-context is now @apollo/client/link/context
apollo-link-error is now @apollo/client/link/error
apollo-link-retry is now @apollo/client/link/retry
apollo-link-schema is now @apollo/client/link/schema
apollo-link-ws is now @apollo/client/link/ws

It is important to note that Apollo Client 3 no longer allows @client fields to be passed through a Link chain. While Apollo Client 2 made it possible to intercept @client fields in Link's like apollo-link-state and apollo-link-schema, Apollo Client 3 enforces that @client fields are local only. This helps ensure Apollo Client's local state story is easier to understand, and prevents unwanted fields from accidentally ending up in network requests (PR #5982).

graphql-anywhere

The graphql-anywhere package’s functionality is no longer included with Apollo Client. You can continue to use the graphql-anywhere package, but Apollo no longer uses it and will not actively support it moving forward.

graphql-tag

The @apollo/client package includes graphql-tag as a dependency and re-exports gql. To simplify your dependencies, we recommend importing gql from @apollo/client and removing all graphql-tag dependencies.

react-apollo

react-apollo v3 is an umbrella package that re-exports the following packages:

@apollo/react-common
@apollo/react-hooks
@apollo/react-components
@apollo/react-hoc
@apollo/react-ssr
@apollo/react-testing

The react-apollo package has been deprecated, and the functionality offered by each of the above packages can now be accessed from @apollo/client directly:

@apollo/react-hooks -> now available directly from @apollo/client
@apollo/react-components -> now available from @apollo/client/react/components
@apollo/react-hoc -> now available from @apollo/client/react/hoc
@apollo/react-ssr -> now available from @apollo/client/react/ssr
@apollo/react-testing -> now available from @apollo/client/testing

Using individual components of Apollo Client 3

Apollo Client 3.0 provides multiple entry points for you to import from. If you only use a particular part of Apollo Client’s functionality, you can import that functionality from its corresponding entry point. By doing so, modern bundlers can omit the remainder of the @apollo/client package from your bundle and reduce its size considerably.

Using Apollo Client without React

Apollo Client 3.0 includes built-in support for React hooks, but it absolutely still supports non-React view layers. To use Apollo Client 3.0 with Vue, Angular, or another view layer of your choosing, import ApolloClient from the @apollo/client/core entry point:

import { ApolloClient } from '@apollo/client/core';

Using apollo-utilities without the rest of Apollo Client

The apollo-utilities package has been removed, but you can access the utilities themselves from the @apollo/client/utilities entry point:

import { isReference, isInlineFragment } from '@apollo/client/utilities';

Using apollo-cache and/or apollo-cache-inmemory without the rest of Apollo Client

The apollo-cache and apollo-cache-inmemory packages have been removed, but if you're interested in using Apollo Client's cache by itself, you can access their contents with the @apollo/client/cache entry point:

import { ApolloCache, InMemoryCache } from '@apollo/client/cache';

Cache improvements

Apollo Client 3.0 introduces powerful improvements to its caching system. Most of these improvements are backward compatible, so most applications will continue to work without any changes to caching logic. However, we highly recommend learning more about the capabilities of the Apollo Client 3.0 cache.

Breaking cache changes

The following cache changes are not backward compatible. Take them into consideration before you upgrade to Apollo Client 3.0.

By default, the InMemoryCache no longer merges the fields of two objects unless those objects have the same unique identifier and that identifier is present in both objects. Additionally, the values of fields with the same name are no longer merged recursively by default. You can define a custom merge function for a field to handle both of these changes for a particular field. You can read more about these changes in Merging non-normalized objects. (PR #5603).
All cache results are now frozen/immutable, as promised in the Apollo Client 2.6 blog post (PR #5153).
FragmentMatcher, HeuristicFragmentMatcher, and IntrospectionFragmentMatcher have all been removed. We recommend using the InMemoryCache’s possibleTypes option instead. For more information, see Defining possibleTypes manually (PR #5073).
The internal representation of normalized data in the cache has changed. If you’re using apollo-cache-inmemory’s public API, then these changes shouldn’t impact you. If you are manipulating cached data directly instead, review PR #5146 for details.
client|cache.writeData have been fully removed. client|cache.writeQuery, client|cache.writeFragment, and/or cache.modify can be used to update the cache. For example:
```
client.writeData({
  data: {
    cartItems: []
  }
});
```
can be converted to:
```
client.writeQuery({
  query: gql`
    query GetCartItems {
      cartItems
    }
  `,
  data: {
    cartItems: []
  }
});
```
For more details around why writeData has been removed, see PR #5923.