@apollo/client/CHANGELOG.md

A fully-featured caching GraphQL client.

# @apollo/client

## 4.0.11

### Patch Changes

- [#13050](https://github.com/apollographql/apollo-client/pull/13050) [`8020829`](https://github.com/apollographql/apollo-client/commit/8020829d8a3bdb3219a37e8d1f7b89179f721037) Thanks [@phryneas](https://github.com/phryneas)! - Replace usage of `findLast` with more backwards-compatible methods.

- [#13049](https://github.com/apollographql/apollo-client/pull/13049) [`05638de`](https://github.com/apollographql/apollo-client/commit/05638deaf598c5bf5d03b82d7deaf57468546229) Thanks [@phryneas](https://github.com/phryneas)! - Fixes an issue where queries starting with `skipToken` or lazy queries from `useLazyQuery` were included in `client.refetchQueries()` before they had been executed for the first time. While generally queries with a `standby` `fetchPolicy` should be included in refetch, these queries never had `variables` passed in, so they should be excluded until they have run once and received their actual variables.

  These queries are now properly excluded from refetch operations until after their initial execution.

  This change adds a new hidden option to `client.watchQuery`, `[variablesUnknownSymbol]`, which may be set `true` for queries starting with a `fetchPolicy` of `standby`. It will only be applied when creating the `ObservableQuery` instance and cannot be changed later. This flag indicates that the query's variables are not yet known, and thus it should be excluded from refetch operations until they are.
  **This option is not meant for everyday use and is intended for framework integrations only.**

## 4.0.10

### Patch Changes

- [#13045](https://github.com/apollographql/apollo-client/pull/13045) [`af4acdc`](https://github.com/apollographql/apollo-client/commit/af4acdc88bd3bac0d697ab300816241e4065842c) Thanks [@phryneas](https://github.com/phryneas)! - Fix memory leak #13036

## 4.0.9

### Patch Changes

- [#12993](https://github.com/apollographql/apollo-client/pull/12993) [`8f3bc9b`](https://github.com/apollographql/apollo-client/commit/8f3bc9b7253a737062dc0d652cd4f8b354f68ccc) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Fix an issue where switching from options with `variables` to `skipToken` with `useSuspenseQuery` and `useBackgroundQuery` would create a new `ObservableQuery`. This could cause unintended refetches where `variables` were absent in the request when the query was referenced with `refetchQueries`.

## 4.0.8

### Patch Changes

- [#12983](https://github.com/apollographql/apollo-client/pull/12983) [`f6d0efa`](https://github.com/apollographql/apollo-client/commit/f6d0efac4d99375c67255aee6d9b2981753b6f55) Thanks [@CarsonF](https://github.com/CarsonF)! - Fix cache.modify() mapping readonly arrays to singular reference

## 4.0.7

### Patch Changes

- [#12950](https://github.com/apollographql/apollo-client/pull/12950) [`5b4f36a`](https://github.com/apollographql/apollo-client/commit/5b4f36a2b249d15e2e8165bd32d9b2fca7e70217) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Don't send `operationType` in the payload sent by `GraphQLWsLink`.

## 4.0.6

### Patch Changes

- [#12937](https://github.com/apollographql/apollo-client/pull/12937) [`3b0d89b`](https://github.com/apollographql/apollo-client/commit/3b0d89bc9dde3eaee9ddf0aec387da43fe71abc0) Thanks [@phryneas](https://github.com/phryneas)! - Fix a problem with `fetchMore` where the loading state wouldn't reset if the result wouldn't result in a data update.

## 4.0.5

### Patch Changes

- [#12920](https://github.com/apollographql/apollo-client/pull/12920) [`e2fc385`](https://github.com/apollographql/apollo-client/commit/e2fc3850ddb2aa756fc44420390ae357daf31948) Thanks [@phryneas](https://github.com/phryneas)! - Fix an invariance type error in the `MockedResponse` type.

## 4.0.4

### Patch Changes

- [#12892](https://github.com/apollographql/apollo-client/pull/12892) [`db8a04b`](https://github.com/apollographql/apollo-client/commit/db8a04b193c157d57d6fe0f187b1892afdda1b7d) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Prevent unhandled rejections from the promise returned by calling the `mutate` function from the `useMutation` hook.

- [#12899](https://github.com/apollographql/apollo-client/pull/12899) [`5352c12`](https://github.com/apollographql/apollo-client/commit/5352c1208e19c93678fef7860a1a87841653eb64) Thanks [@phryneas](https://github.com/phryneas)! - Fix an issue when `invariant` is called by external libraries when no dev error message handler is loaded.

- [#12895](https://github.com/apollographql/apollo-client/pull/12895) [`71f2517`](https://github.com/apollographql/apollo-client/commit/71f2517132a34563a14934f3971666b3691710f9) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Support `skipToken` with `useQuery` to provide a more type-safe way to skip query execution.

  ```ts
  import { skipToken, useQuery } from "@apollo/client/react";

  // Use `skipToken` in place of `skip: true` for better type safety
  // for required variables
  const { data } = useQuery(QUERY, id ? { variables: { id } } : skipToken);
  ```

  Note: this change is provided as a patch within the 4.0 minor version because the changes to TypeScript validation with required variables in version 4.0 made using the `skip` option more difficult.

- [#12900](https://github.com/apollographql/apollo-client/pull/12900) [`c0d5be7`](https://github.com/apollographql/apollo-client/commit/c0d5be7cbbb1b1f7771962eb2ae0e173de743265) Thanks [@phryneas](https://github.com/phryneas)! - Use named export `equal` instead of default from `"@wry/equality"`

## 4.0.3

### Patch Changes

- [#12887](https://github.com/apollographql/apollo-client/pull/12887) [`6f6ca47`](https://github.com/apollographql/apollo-client/commit/6f6ca47e9f5e80ee9c98fca2639b5cba6317fbbf) Thanks [@phryneas](https://github.com/phryneas)! - Fix accidental deep re-export from `/react` out of `/react/internals`

- [#12890](https://github.com/apollographql/apollo-client/pull/12890) [`019b422`](https://github.com/apollographql/apollo-client/commit/019b4224147a5a8709de54c4474e126619dd2469) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Ensure the `variables` option for `useMutation` provides proper IntelliSense suggestions.

## 4.0.2

### Patch Changes

- [#12880](https://github.com/apollographql/apollo-client/pull/12880) [`56fac52`](https://github.com/apollographql/apollo-client/commit/56fac522549eaed5494097dc0098ea7a558382a0) Thanks [@phryneas](https://github.com/phryneas)! - restore `getMemoryInternals` access in dev builds

## 4.0.1

### Patch Changes

- [#12876](https://github.com/apollographql/apollo-client/pull/12876) [`b00f231`](https://github.com/apollographql/apollo-client/commit/b00f231e5f10a23178cf7a2c69a4e13cd959ab45) Thanks [@phryneas](https://github.com/phryneas)! - Fix CJS build output for `invariantErrorCodes`

- [#12866](https://github.com/apollographql/apollo-client/pull/12866) [`0d1614a`](https://github.com/apollographql/apollo-client/commit/0d1614a9dfca2b1bcf4ea40095cc9018d6314532) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Export `isNetworkStatusInFlight` from `@apollo/client/utilities`. Add `isNetworkStatusSettled` to `@apollo/client/utilities` and re-export it from `@apollo/client` with a deprecation.

## 4.0.0

# Apollo Client 4.0 Release Notes

Apollo Client 4.0 delivers a more modern, efficient, and type-safe GraphQL client experience through various architectural improvements and API refinements. This release focuses on developer experience, bundle size optimization, and framework flexibility.

## Key Improvements

### 🎯 Framework-Agnostic Core

Apollo Client 4.0 separates React functionality from the core library, making `@apollo/client` truly framework-agnostic. React exports now live in `@apollo/client/react`, allowing developers to use Apollo Client with any JavaScript framework without React dependencies.

### 📦 Smaller Bundle Sizes

- **Opt-in Local State Management**: The `@client` directive functionality is now opt-in via the `LocalState` class, reducing bundle size when not using local state
- **Modern Build Target**: Transpiled to target `since 2023, node >= 20, not dead`, leveraging modern JavaScript features for better performance
- **Improved Tree-Shaking**: Proper `exports` field in package.json enables better dead code elimination

### 💥 Unified Error Handling

Apollo Client 4.0 completely reimagines error handling for better clarity and debugging:

- `ApolloError` removed in favor of specific error classes
- Unification of errors to a single `error` property
- Network errors now respect `errorPolicy` settings
- External errors passed through without wrapping
- New, more granular error classes with static `.is()` methods for robust type narrowing

### 🔧 Enhanced TypeScript Support

- **Namespaced Types**: Types are now colocated with their APIs (e.g., `useQuery.Options` instead of `QueryHookOptions`)
- **Precise Return Types**: Return types accurately reflect the options passed (e.g., `returnPartialData` makes `data` type `DeepPartial<TData>`)
- **Stricter Type Safety**: Required variables are now enforced more consistently throughout the client
- **New `dataState` Property**: Enables accurate type narrowing of query results
- **Module Augmentation**: Custom context types via declaration merging instead of fragile generics
- **Customizable Type Implementations**: Select types can now be customized to provide your own type implementation to seamlessly integrate with external tools such as GraphQL Codegen or `gql.tada`

### ⚡ Modern Observable Implementation

Apollo Client 4.0 migrates from `zen-observable` to **RxJS**, providing the industry-standard Observable implementation backed by a rich ecosystem of utilities.

## Major Features

### Unified Error Handling

Apollo Client 4.0 completely reimagines error handling for better clarity and debugging:

**Key Changes:**

- `ApolloError` removed in favor of specific error classes
- Network errors now respect `errorPolicy` settings
- External errors passed through without wrapping
- New error classes with static `.is()` methods for type checking

**Error Classes:**

- `CombinedGraphQLErrors` - GraphQL errors from the server
- `ServerError` - Non-GraphQL server errors
- `ServerParseError` - Server response parsing errors
- `UnconventionalError` - Wrapper for non-error thrown values
- `LinkError` - Errors from the link chain (via `.is()` check)

**Migration Example:**

```typescript
// Apollo Client 3
if (error instanceof ApolloError) {
  console.log(error.graphQLErrors);
  console.log(error.networkError);
}

// Apollo Client 4
import { CombinedGraphQLErrors } from "@apollo/client";

if (CombinedGraphQLErrors.is(error)) {
  console.log(error.errors); // GraphQL errors
} else if (error) {
  console.log(error.message); // Other errors
}
```

### The `dataState` Property

A new property that clearly indicates the completeness of query results:

**Values:**

- `empty` - No data available (`data` is `undefined`)
- `partial` - Incomplete data from cache when `returnPartialData` is `true`
- `streaming` - Incomplete data from a deferred query still streaming
- `complete` - Fully satisfied query result

**Benefits:**

- Accurate TypeScript type narrowing
- Clear loading state distinction
- Better handling of partial results

```typescript
const { data, dataState } = useQuery(MY_QUERY);

if (dataState === "complete") {
  // TypeScript knows data is fully populated
  console.log(data.allFields);
} else if (dataState === "partial") {
  // TypeScript knows data might be missing fields
  console.log(data?.someField);
}
```

### Pluggable Incremental Delivery (`@defer` Support)

Apollo Client 4.0 makes incremental delivery configurable and future-proof:

```typescript
import { Defer20220824Handler } from "@apollo/client/incremental";

const client = new ApolloClient({
  // ...
  incrementalHandler: new Defer20220824Handler(),
});
```

**Available Handlers:**

- `NotImplementedHandler` - Default, throws if `@defer` is used
- `Defer20220824Handler` - Apollo Router format support (also aliased as `GraphQL17Alpha2Handler`)

### Local State Management Improvements

Local state is now opt-in via the `LocalState` class:

```typescript
import { LocalState } from "@apollo/client/local-state";

const client = new ApolloClient({
  cache,
  localState: new LocalState({
    resolvers: {
      Query: {
        myField: () => "Hello World",
      },
    },
  }),
});
```

**Resolver Context Changes:**

```typescript
// Apollo Client 3
const resolver = (parent, args, context, info) => {
  const { cache } = context;
};

// Apollo Client 4
const resolver = (parent, args, context, info) => {
  const { client, requestContext, phase } = context;
  const cache = client.cache;
};
```

## React-Specific Improvements

### More Predictable Hooks

**`useLazyQuery` Overhaul:**

- No longer accepts `variables` or `context` options (pass to `execute` instead)
- `execute` function only accepts `variables` and `context`
- Cannot be called during render or SSR
- Automatic cancellation of in-flight queries when new ones start

**`useMutation` Changes:**

- Removed `ignoreResults` option - use `client.mutate` directly for fire-and-forget mutations

**`useQuery` Changes:**

- `notifyOnNetworkStatusChange` now defaults to `true`
- Removed deprecated `onCompleted` and `onError` callbacks

### New SSR API

The new `prerenderStatic` API replaces deprecated SSR functions:

```typescript
import { prerenderStatic } from "@apollo/client/react/ssr";

// Works with React 19's prerender APIs
const html = await prerenderStatic(<App />, {
  client,
});
```

### React Compiler Support

Pre-compiled React hooks optimized by the React Compiler:

```typescript
// Use compiled hooks for potential performance improvements
import { useQuery } from "@apollo/client/react/compiled";
```

The compiled hooks are built with React Compiler v19.1.0-rc.2 and include a runtime polyfill for compatibility with React 17+.

## Link System Evolution

### All Links Now Classes

Migration from creator functions to classes:

```typescript
// Apollo Client 3
import { createHttpLink, setContext } from "@apollo/client";
const httpLink = createHttpLink({ uri: "/graphql" });
const authLink = setContext((operation, prevContext) => {
  /*...*/
});

// Apollo Client 4
import { HttpLink, SetContextLink } from "@apollo/client";
const httpLink = new HttpLink({ uri: "/graphql" });
const authLink = new SetContextLink((prevContext, operation) => {
  /*...*/
});
```

### ErrorLink Changes

```typescript
// Apollo Client 3
onError(({ graphQLErrors, networkError }) => {
  // Handle errors separately
});

// Apollo Client 4
new ErrorLink(({ error }) => {
  if (CombinedGraphQLErrors.is(error)) {
    // Handle GraphQL errors
  } else if (error) {
    // Handle other errors
  }
});
```

## Migration Tools

### Automated Codemod

Apollo Client 4.0 provides a comprehensive codemod to automate migration:

```bash
# Basic usage
npx @apollo/client-codemod-migrate-3-to-4 src

# TypeScript projects (run separately)
npx @apollo/client-codemod-migrate-3-to-4 --parser ts --extensions ts src
npx @apollo/client-codemod-migrate-3-to-4 --parser tsx --extensions tsx src
```

The codemod handles:

1. **Import updates** - Moves React imports to `@apollo/client/react`
2. **Type migrations** - Updates types to new namespaced locations
3. **Link updates** - Converts creator functions to classes
4. **Removed exports** - Moves to `@apollo/client/v4-migration` with migration instructions

## Breaking Changes Summary

### Installation

```bash
# RxJS is now a peer dependency
npm install @apollo/client graphql rxjs
```

### ApolloClient Constructor

- `link` option is now required (no more implicit `HttpLink` creation)
- `uri`, `headers`, `credentials` removed - use `HttpLink` directly
- `name` and `version` moved to `clientAwareness` option
- `resolvers` moved to `LocalState` constructor
- `connectToDevTools` replaced with `devtools.enabled`
- `disableNetworkFetches` renamed to `prioritizeCacheValues`

### Type System

- Removed `TContext` and `TCacheShape` generics
- Types moved to namespaces (see migration guide for full list)
- Custom context via module augmentation

### Observable Changes

- Requires calling `.pipe()` for transformations
- Use RxJS operators instead of method chaining

### Testing

- `MockedProvider` now has realistic delays by default (20-50ms)
- `createMockClient` removed - use `MockLink` directly

## Performance & Build Improvements

- **Modern JavaScript**: No downlevel transpilation for modern features
- **No Polyfills**: Cleaner bundles, bring your own if needed
- **Development Mode**: Controlled via export conditions, not global `__DEV__`
- **ESM Support**: Proper `exports` field for better module resolution
- **Source Maps**: Fixed and improved for better debugging

## Deprecations & Removals

### Removed Packages/Exports

- React render prop components (`@apollo/client/react/components`)
- Higher-order components (`@apollo/client/react/hoc`)
- `@apollo/client/react/parser`
- `@apollo/client/utilities/globals`

## Upgrade Path

1. **Update to Apollo Client 3.14** first for deprecation warnings
2. **Install peer dependencies**: `npm install rxjs`
3. **Run the codemod** to automate import and type updates
4. **Update ApolloClient initialization** (explicit `HttpLink`, `LocalState` if needed)
5. **Review error handling** - update to use new error classes
6. **Test thoroughly** - especially SSR, error handling, and local state

## Resources

- [Migration Guide](https://www.apollographql.com/docs/react/migrating/apollo-client-4-migration)
- [Changelog](https://github.com/apollographql/apollo-client/blob/main/CHANGELOG.md)

## Acknowledgments

Apollo Client 4.0 represents years of community feedback and contributions. Thank you to all our contributors, early adopters, and the entire GraphQL community for making this release possible.

<details>

<summary>

### Major Changes

</summary>

- [#12644](https://github.com/apollographql/apollo-client/pull/12644) [`fe2f005`](https://github.com/apollographql/apollo-client/commit/fe2f005c34913ae082b96a807dc240e2785d50bd) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Replace the `result` property on `ServerError` with `bodyText`. `bodyText` is set to the raw string body. `HttpLink` and `BatchHttpLink` no longer try and parse the response body as JSON when a `ServerError` is thrown.

- [#12673](https://github.com/apollographql/apollo-client/pull/12673) [`cee90ab`](https://github.com/apollographql/apollo-client/commit/cee90abcd2a9c91c5fdf872cf2d1c12deaa6593e) Thanks [@phryneas](https://github.com/phryneas)! - The `includeExtensions` option of `HttpLink` and `BatchHttpLink` now defaults
  to `true`.

  If `includeExtensions` is `true`, but `extensions` is not set or empty, extensions
  will not be included in outgoing requests.

- [#12686](https://github.com/apollographql/apollo-client/pull/12686) [`dc4b1d0`](https://github.com/apollographql/apollo-client/commit/dc4b1d0d2479a37067113b7bd161a550fb8e4df6) Thanks [@jerelmiller](https://github.com/jerelmiller)! - A `@defer` query that has not yet finished streaming is now considered loading and thus the `loading` flag will be `true` until the response has completed. A new `NetworkStatus.streaming` value has been introduced and will be set as the `networkStatus` while the response is streaming.

- [#12539](https://github.com/apollographql/apollo-client/pull/12539) [`dd0d6d6`](https://github.com/apollographql/apollo-client/commit/dd0d6d6d96d8b810e30dc2fdee2ac8a2477d0017) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `onError` link now uses a single `error` property to report the error that caused the link callback to be called. This will be an instance of `CombinedGraphQLErrors` in the event GraphQL errors were emitted from the terminating link, `CombinedProtocolErrors` if the terminating link emitted protocol errors, or the unwrapped error type if any other non-GraphQL error was thrown or emitted.

  ```diff
  - const errorLink = onError(({ graphQLErrors, networkError, protocolErrors }) => {
  -   graphQLErrors.forEach(error => console.log(error.message));
  + const errorLink = onError(({ error }) => {
  +   if (error.name === 'CombinedGraphQLErrors') {
  +     error.errors.forEach(rawError => console.log(rawError.message));
  +   }
  });
  ```

- [#12586](https://github.com/apollographql/apollo-client/pull/12586) [`605db8e`](https://github.com/apollographql/apollo-client/commit/605db8e94fe2ce74c0a395f38f6873d40f431365) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove the `typeDefs` option from `ApolloClient`.

- [#12384](https://github.com/apollographql/apollo-client/pull/12384) [`6aa6fd3`](https://github.com/apollographql/apollo-client/commit/6aa6fd316cfdb31ebbe3e3133cca2965604e7ca1) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove the `asyncMap` utility function. Instead use one of the RxJS operators that creates Observables from promises, such as `from`.

- [#12398](https://github.com/apollographql/apollo-client/pull/12398) [`8cf5077`](https://github.com/apollographql/apollo-client/commit/8cf5077bed1ab46fdd32c5e253071506c0076064) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Removes the `isApolloError` utility function to check if the error object is an `ApolloError` instance. Use `instanceof` to check for more specific error types that replace `ApolloError`.

- [#12379](https://github.com/apollographql/apollo-client/pull/12379) [`ef892b4`](https://github.com/apollographql/apollo-client/commit/ef892b4dc505b02049525f9aba32c51f1c00c922) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Removes the `addTypename` option from `InMemoryCache` and `MockedProvider`. `__typename` is now always added to the outgoing query document when using `InMemoryCache` and cannot be disabled.

  If you are using `<MockedProvider />` with `addTypename={false}`, ensure that your mocked responses include a `__typename` field. This will ensure cache normalization kicks in and behaves more like production.

- [#12396](https://github.com/apollographql/apollo-client/pull/12396) [`00f3d0a`](https://github.com/apollographql/apollo-client/commit/00f3d0a674eede1f909092283041cf8ac8d1b576) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove the deprecated `errors` property from `useQuery` and `useLazyQuery`. Read errors from the `error` property instead.

- [#12809](https://github.com/apollographql/apollo-client/pull/12809) [`e2a0be8`](https://github.com/apollographql/apollo-client/commit/e2a0be8c3f8b242706f90e0dcc022628992a8ae8) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `operation.getContext` now returns a `Readonly<OperationContext>` type.

- [#12809](https://github.com/apollographql/apollo-client/pull/12809) [`e2a0be8`](https://github.com/apollographql/apollo-client/commit/e2a0be8c3f8b242706f90e0dcc022628992a8ae8) Thanks [@jerelmiller](https://github.com/jerelmiller)! - The `ApolloLink.Request` (i.e. `GraphQLRequest`) passed to `ApolloLink.execute` no longer accepts `operationName` and `operationType` options. These properties are derived from the `query` and set on the returned `ApolloLink.Operation` type.

- [#12712](https://github.com/apollographql/apollo-client/pull/12712) [`bbb2b61`](https://github.com/apollographql/apollo-client/commit/bbb2b61d259da54560a79813b130a977dae10523) Thanks [@jerelmiller](https://github.com/jerelmiller)! - An error is now thrown when trying to call `fetchMore` on a `cache-only` query.

- [#12222](https://github.com/apollographql/apollo-client/pull/12222) [`d1a9054`](https://github.com/apollographql/apollo-client/commit/d1a905461d4378522c3257de00afba2ae8decd22) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Drop support for React 16.

- [#12787](https://github.com/apollographql/apollo-client/pull/12787) [`8ce31fa`](https://github.com/apollographql/apollo-client/commit/8ce31fae54b1ae76c557f361cc946858cb2ff66b) Thanks [@phryneas](https://github.com/phryneas)! - Remove `DataProxy` namespace and interface.

- [#12450](https://github.com/apollographql/apollo-client/pull/12450) [`876d070`](https://github.com/apollographql/apollo-client/commit/876d07042cf3348b3769b2bb415aa5f70ce9844c) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove `TSerialized` generic argument to `ApolloCache`. The `ApolloCache` base cache abstraction now returns `unknown` for `cache.extract` which can be overridden by a cache subclass.

- [#12614](https://github.com/apollographql/apollo-client/pull/12614) [`d2851e2`](https://github.com/apollographql/apollo-client/commit/d2851e2c74541995760a86904b1e3ab4bd736e62) Thanks [@jerelmiller](https://github.com/jerelmiller)! - The `getCacheKey` function is no longer available from `operation.getContext()` in the link chain. Use `operation.client.cache.identify(obj)` in the link chain instead.

- [#12376](https://github.com/apollographql/apollo-client/pull/12376) [`a0c996a`](https://github.com/apollographql/apollo-client/commit/a0c996a816fbb6a2323231c0422d1c8a3e20cbaf) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove deprecated `ignoreResults` option from `useMutation`. If you don't want to synchronize component state with the mutation, use `useApolloClient` to access your client instance and use `client.mutate` directly.

- [#12644](https://github.com/apollographql/apollo-client/pull/12644) [`fe2f005`](https://github.com/apollographql/apollo-client/commit/fe2f005c34913ae082b96a807dc240e2785d50bd) Thanks [@jerelmiller](https://github.com/jerelmiller)! - More strictly adhere to the [GraphQL over HTTP spec](https://graphql.github.io/graphql-over-http/draft/). This change adds support for the `application/graphql-response+json` media type and modifies the behavior of the `application/json` media type.

  - The client will parse the response as a well-formed GraphQL response when the server encodes `content-type` using `application/graphql-response+json` with a non-200 status code.
  - The client will now throw a `ServerError` when the server encodes `content-type` using `application/json` and returns a non-200 status code.
  - The client will now throw a `ServerError` when the server encodes using any other `content-type` and returns a non-200 status code.

  NOTE: If you use a testing utility to mock requests in your test, you may experience different behavior than production if your testing utility responds as `application/json` but your production server responds as `application/graphql-response+json`. If a `content-type` header is not set, the client interprets the response as `application/json`.

- [#12600](https://github.com/apollographql/apollo-client/pull/12600) [`34ff6aa`](https://github.com/apollographql/apollo-client/commit/34ff6aa25b47c3e84d0b18e2c69bc995814bf2f2) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Move most of the utilities in `@apollo/client/utilities` to `@apollo/client/utilities/internal`. Many of the utilities exported from the `@apollo/client/utilities` endpoint were not considered stable.

  As a result of this change, utilities or types exported from `@apollo/client/utilities` are now documented and considered stable and will not undergo breaking changes.

- [#12513](https://github.com/apollographql/apollo-client/pull/12513) [`9c3207c`](https://github.com/apollographql/apollo-client/commit/9c3207c44ddad1f8b845c09495d6c070ace8de7b) Thanks [@phryneas](https://github.com/phryneas)! - Removed the `@apollo/client/react/context` and `@apollo/client/react/hooks` entry points. Please use `@apollo/client/react` instead.

- [#12384](https://github.com/apollographql/apollo-client/pull/12384) [`6aa6fd3`](https://github.com/apollographql/apollo-client/commit/6aa6fd316cfdb31ebbe3e3133cca2965604e7ca1) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Unusubscribing from `ObservableQuery` while a request is in flight will no longer terminate the request by unsubscribing from the link observable.

- [#12463](https://github.com/apollographql/apollo-client/pull/12463) [`3868df8`](https://github.com/apollographql/apollo-client/commit/3868df81f973dc7b5a79fadf4dc1b0e291003b7f) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `ObservableQuery.setOptions` has been removed as it was an alias of `reobserve`. Prefer using `reobserve` directly instead.

  ```diff
  const observable = client.watchQuery(options);

  // Use reobserve to set new options and reevaluate the query
  - observable.setOptions(newOptions);
  + observable.reobserve(newOptions);
  ```

  As a result of this change, `reobserve` has been marked for public use and is no longer considered an internal API. The `newNetworkStatus` argument has been removed to facilitate this change.

- [#12478](https://github.com/apollographql/apollo-client/pull/12478) [`5ea6a45`](https://github.com/apollographql/apollo-client/commit/5ea6a45b3ec2f0d526abe78ae03c42bb519f87c7) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove `variables` from the result returned from `useSubscription`.

- [#12735](https://github.com/apollographql/apollo-client/pull/12735) [`5159880`](https://github.com/apollographql/apollo-client/commit/51598808851e16af722baaefbd1f90534332e07a) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove deprecated `resultCacheMaxSize` option from `InMemoryCache` options.

- [#12673](https://github.com/apollographql/apollo-client/pull/12673) [`cee90ab`](https://github.com/apollographql/apollo-client/commit/cee90abcd2a9c91c5fdf872cf2d1c12deaa6593e) Thanks [@phryneas](https://github.com/phryneas)! - The `ApolloClient` constructor options `name` and `version` that are used to
  configure the client awareness feature have moved onto a `clientAwareness` key.

  ```diff
  const client = new ApolloClient({
    // ..
  -  name: "my-app",
  -  version: "1.0.0",
  +  clientAwareness: {
  +    name: "my-app",
  +    version: "1.0.0",
  +  },
  });
  ```

- [#12367](https://github.com/apollographql/apollo-client/pull/12367) [`e6af35e`](https://github.com/apollographql/apollo-client/commit/e6af35ed30c732ad834e6c524bc9ce5adbe5f706) Thanks [@jerelmiller](https://github.com/jerelmiller)! - The `previousData` property on `useLazyQuery` will now change only when `data` changes. Previously `previousData` would change to the same value as `data` while the query was loading.

- [#12690](https://github.com/apollographql/apollo-client/pull/12690) [`5812759`](https://github.com/apollographql/apollo-client/commit/5812759b6659df49277635e89492c0d72c3b57d6) Thanks [@phryneas](https://github.com/phryneas)! - Aliasing any other field to `__typename` is now forbidden.

- [#12556](https://github.com/apollographql/apollo-client/pull/12556) [`c3fceda`](https://github.com/apollographql/apollo-client/commit/c3fceda86c5e0f499d0b5fa54ea7dc4c4391ae2c) Thanks [@phryneas](https://github.com/phryneas)! - `ObservableQuery` will now keep previous `data` around when emitting a `loading` state, unless `query` or `variables` changed.
  Note that `@exports` variables are not taken into account for this, so `data` will stay around even if they change.

- [#12776](https://github.com/apollographql/apollo-client/pull/12776) [`bce9b74`](https://github.com/apollographql/apollo-client/commit/bce9b7448a226b109cbe8f14911503fb09f37825) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Report masked fragments as complete even when a nested masked fragment contains partial data.

- [#12788](https://github.com/apollographql/apollo-client/pull/12788) [`4179446`](https://github.com/apollographql/apollo-client/commit/417944677d2e79606b0f6cabd8d5d8b2063c876b) Thanks [@phryneas](https://github.com/phryneas)! - `TVariables` now always `extends OperationVariables` in all interfaces.

- [#12224](https://github.com/apollographql/apollo-client/pull/12224) [`51e6c0f`](https://github.com/apollographql/apollo-client/commit/51e6c0f8657d20cedc570c6e9a244f877047dd61) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove deprecated `partialRefetch` option.

- [#12407](https://github.com/apollographql/apollo-client/pull/12407) [`8b1390b`](https://github.com/apollographql/apollo-client/commit/8b1390bf0050c6bd4d5a32b67c3b96369d0552d4) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Calling `refetch` with new variables will now set the `networkStatus` to `refetch` instead of `setVariables`.

- [#12476](https://github.com/apollographql/apollo-client/pull/12476) [`6afff60`](https://github.com/apollographql/apollo-client/commit/6afff60beece953406af2cbe07f7ccbf973cadaa) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Subscriptions now emit a `SubscribeResult` instead of a `FetchResult`. As a result, the `errors` field has been removed in favor of `error`.

- [#12457](https://github.com/apollographql/apollo-client/pull/12457) [`32e85ea`](https://github.com/apollographql/apollo-client/commit/32e85ea9eb93c1ffb10d6f70e9e2775e1326e9aa) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Network errors triggered by queries now adhere to the `errorPolicy`. This means that GraphQL errors and network errors now behave the same way. Previously promise-based APIs, such as `client.query`, would reject the promise with the network error even if `errorPolicy` was set to `ignore`. The promise is now resolved with the `error` property set to the network error instead.

- [#12840](https://github.com/apollographql/apollo-client/pull/12840) [`83e132a`](https://github.com/apollographql/apollo-client/commit/83e132ab1bacb3293da61dd4519379e36a1fb090) Thanks [@phryneas](https://github.com/phryneas)! - If you use an incremental delivery handler, you now have to explicitly opt into adding the chunk types to the `ApolloLink.Result` type.

  ```ts title="apollo-client.d.ts
  import { Defer20220824Handler } from "@apollo/client/incremental";

  declare module "@apollo/client" {
    export interface TypeOverrides extends Defer20220824Handler.TypeOverrides {}
  }
  ```

- [#12712](https://github.com/apollographql/apollo-client/pull/12712) [`bbb2b61`](https://github.com/apollographql/apollo-client/commit/bbb2b61d259da54560a79813b130a977dae10523) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `cache-only` queries are no longer refetched when calling `client.reFetchObservableQueries` when `includeStandby` is `true`.

- [#12808](https://github.com/apollographql/apollo-client/pull/12808) [`8e31a23`](https://github.com/apollographql/apollo-client/commit/8e31a2303b18f6fc4d8ec1cf4c01bf26b90f3f0b) Thanks [@phryneas](https://github.com/phryneas)! - HTTP Multipart handling will now throw an error if the connection closed before the final boundary has been received.
  Data after the final boundary will be ignored.

- [#12384](https://github.com/apollographql/apollo-client/pull/12384) [`6aa6fd3`](https://github.com/apollographql/apollo-client/commit/6aa6fd316cfdb31ebbe3e3133cca2965604e7ca1) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove the `iterateObserversSafely` utility function.

- [#12825](https://github.com/apollographql/apollo-client/pull/12825) [`292b949`](https://github.com/apollographql/apollo-client/commit/292b949e9e1d10a715e0fd403737361f91432fbf) Thanks [@jerelmiller](https://github.com/jerelmiller)! - The `serializeFetchParameter` helper is no longer exported and `JSON.stringify` is used directly. As such, the `ClientParseError` type has also been removed in favor of throwing any JSON serialize errors directly.

- [#12595](https://github.com/apollographql/apollo-client/pull/12595) [`60bb49c`](https://github.com/apollographql/apollo-client/commit/60bb49ccea9aecf3e6a212b5a1f71907e60af886) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove the `@apollo/client/testing/experimental` test utilities. Use [GraphQL Testing Library](https://github.com/apollographql/graphql-testing-library) instead.

- [#12718](https://github.com/apollographql/apollo-client/pull/12718) [`ecfc02a`](https://github.com/apollographql/apollo-client/commit/ecfc02a37908b58d1f799f0e817cdeab98482720) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Version bump only to release latest as `rc`.

- [#12470](https://github.com/apollographql/apollo-client/pull/12470) [`d32902f`](https://github.com/apollographql/apollo-client/commit/d32902f26a4c5dea30421ee52aeea52df3e5334e) Thanks [@phryneas](https://github.com/phryneas)! - `ssrMode`, `ssrForceFetchDelay` and `disableNetworkFetches` have been reworked:

  Previously, a `ObservableQuery` created by `client.query` or `client.watchQuery`
  while one of those were active would permanently be changed from a `fetchPolicy`
  of `"network-only"` or `"cache-and-network"` to `"cache-first"`, and stay that way
  even long after `disableNetworkFetches` would have been deactivated.

  Now, the `ObservableQuery` will keep their original `fetchPolicy`, but queries
  made during `disableNetworkFetches` will just apply the `fetchPolicy` replacement
  at request time, just for that one request.

  `ApolloClient.disableNetworkFetches` has been renamed to `ApolloClient.prioritizeCacheValues` to better reflect this behaviour.

- [#12559](https://github.com/apollographql/apollo-client/pull/12559) [`49ace0e`](https://github.com/apollographql/apollo-client/commit/49ace0e2119b7fd5997dcf051002ebd4ba2e0bc4) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `ObservableQuery.variables` can now be reset back to empty when calling `reobserve` with `variables: undefined`. Previously the `variables` key would be ignored so `variables` would remain unchanged.

- [#12559](https://github.com/apollographql/apollo-client/pull/12559) [`49ace0e`](https://github.com/apollographql/apollo-client/commit/49ace0e2119b7fd5997dcf051002ebd4ba2e0bc4) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `never` is no longer supported as a valid `TVariables` generic argument for APIs that require `variables` as part of its type. Use `Record<string, never>` instead.

- [#12735](https://github.com/apollographql/apollo-client/pull/12735) [`5159880`](https://github.com/apollographql/apollo-client/commit/51598808851e16af722baaefbd1f90534332e07a) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove deprecated `connectToDevtools` option from `ApolloClientOptions`. Use `devtools.enabled` instead.

- [#12576](https://github.com/apollographql/apollo-client/pull/12576) [`a92ff78`](https://github.com/apollographql/apollo-client/commit/a92ff780abee60896bb9632867e90c82d0829255) Thanks [@jerelmiller](https://github.com/jerelmiller)! - The `cache` and `forceFetch` properties are no longer available on context when calling `operation.getContext()`. `cache` can be accessed through the `operation` with `operation.client.cache` instead. `forceFetch` has been replaced with `queryDeduplication` which specifies whether `queryDeduplication` was enabled for the request or not.

- [#12533](https://github.com/apollographql/apollo-client/pull/12533) [`73221d8`](https://github.com/apollographql/apollo-client/commit/73221d87bd5640986f86fe3ee50c63ed49834cbb) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove the `onError` and `setOnError` methods from `ApolloLink`. `onError` was only used by `MockLink` to rewrite errors if `setOnError` was used.

- [#12485](https://github.com/apollographql/apollo-client/pull/12485) [`d338303`](https://github.com/apollographql/apollo-client/commit/d3383033d306b7d66e90f5f3170c24453cd76464) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Throw an error for queries and mutations if the link chain completes without emitting a value.

- [#12556](https://github.com/apollographql/apollo-client/pull/12556) [`c3fceda`](https://github.com/apollographql/apollo-client/commit/c3fceda86c5e0f499d0b5fa54ea7dc4c4391ae2c) Thanks [@phryneas](https://github.com/phryneas)! - Removed `getLastResult`, `getLastError` and `resetLastResults` from `ObservableQuery`

- [#12663](https://github.com/apollographql/apollo-client/pull/12663) [`01512f2`](https://github.com/apollographql/apollo-client/commit/01512f2429dd394fb72b8ba9284047a09ade666f) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Unsubscribing from an `ObservableQuery` before a value has been emitted will remove the query from the tracked list of queries and will no longer be eligible for query deduplication.

- [#12809](https://github.com/apollographql/apollo-client/pull/12809) [`e2a0be8`](https://github.com/apollographql/apollo-client/commit/e2a0be8c3f8b242706f90e0dcc022628992a8ae8) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `operation.operationType` is now a non-null `OperationTypeNode`. It is now safe to compare this value without having to check for `undefined`.

- [#12398](https://github.com/apollographql/apollo-client/pull/12398) [`8cf5077`](https://github.com/apollographql/apollo-client/commit/8cf5077bed1ab46fdd32c5e253071506c0076064) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Apollo Client no longer wraps errors in `ApolloError`. `ApolloError` has been replaced with separate error classes depending on the cause of the error. As such, APIs that return an `error` property have been updated to use the generic `Error` type. Use `instanceof` to check for more specific error types.

  ## Migration guide

  `ApolloError` encapsulated 4 main error properties. The type of error would determine which property was set:

  - `graphqlErrors` - Errors returned from the `errors` field by the GraphQL server
  - `networkError` - Any non-GraphQL error that caused the query to fail
  - `protocolErrors` - Transport-level errors that occur during [multipart HTTP subscriptions](https://www.apollographql.com/docs/graphos/routing/operations/subscriptions/multipart-protocol)
  - `clientErrors` - A space to define custom errors. Mostly unused.

  These errors were mutally exclusive, meaning both `networkError` and `graphqlErrors` were never set simultaneously. The following replaces each of these fields from `ApolloError`.

  ### `graphqlErrors`

  GraphQL errors are now encapsulated in a `CombinedGraphQLErrors` instance. You can access the raw GraphQL errors via the `errors` property.

  ```js
  import { CombinedGraphQLErrors } from "@apollo/client";

  // ...

  const { error } = useQuery(query);

  if (error && error instanceof CombinedGraphQLErrors) {
    console.log(error.errors);
  }
  ```

  ### `networkError`

  Network errors are no longer wrapped and are instead passed through directly.

  ```js
  const client = new ApolloClient({
    link: new ApolloLink(() => {
      return new Observable((observer) => {
        observer.error(new Error("Test error"));
      });
    }),
  });

  // ...

  const { error } = useQuery(query);

  // error is `new Error('Test error')`;
  ```

  ### `protocolErrors`

  Protocol errors are now encapsulated in a `CombinedProtocolErrors` instance. You can access the raw protocol errors via the `errors` property.

  ```js
  import { CombinedProtocolErrors } from "@apollo/client";

  // ...

  const { error } = useSubscription(subscription);

  if (error && error instanceof CombinedProtocolErrors) {
    console.log(error.errors);
  }
  ```

  ### `clientErrors`

  These were unused by the client and have no replacement. Any non-GraphQL or non-protocol errors are now passed through unwrapped.

  ### Strings as errors

  If the link sends a string error, Apollo Client will wrap this in an `Error` instance. This ensures `error` properties are guaranteed to be of type `Error`.

  ```js
  const client = new ApolloClient({
    link: new ApolloLink(() => {
      return new Observable((observer) => {
        // Oops we sent a string instead of wrapping it in an `Error`
        observer.error("Test error");
      });
    }),
  });

  // ...

  const { error } = useQuery(query);

  // The error string is wrapped and returned as `new Error('Test error')`;
  ```

  ### Non-error types

  If the link chain sends any other object type as an error, Apollo Client will wrap this in an `UnknownError` instance with the [`cause`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause) set to the original object. This ensures `error` properties are guaranteed to be of type `Error`.

  ```js
  const client = new ApolloClient({
    link: new ApolloLink(() => {
      return new Observable((observer) => {
        observer.error({ message: "Not a proper error type" });
      });
    }),
  });

  // ...

  const { error } = useQuery(query);

  // error is an `UnknownError` instance. error.cause returns the original object.
  ```

- [#12809](https://github.com/apollographql/apollo-client/pull/12809) [`e2a0be8`](https://github.com/apollographql/apollo-client/commit/e2a0be8c3f8b242706f90e0dcc022628992a8ae8) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `operation.operationName` is now set as `string | undefined` where `undefined` represents an anonymous query. Previously `operationName` would return an empty string as the `operationName` for anonymous queries.

- [#12450](https://github.com/apollographql/apollo-client/pull/12450) [`876d070`](https://github.com/apollographql/apollo-client/commit/876d07042cf3348b3769b2bb415aa5f70ce9844c) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove the `TCacheShape` generic argument to `ApolloClient`. `client.extract()` now returns `unknown` by default. You will either need to type-cast this to the expected serialized shape, or use the `cache.extract()` directly from the subclass to get more specific types.

- [#12774](https://github.com/apollographql/apollo-client/pull/12774) [`511b4f3`](https://github.com/apollographql/apollo-client/commit/511b4f3e792a75aa5aa27b335e8119dbc2a9c254) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Apply document transforms before reading data from the cache for `client.readQuery`, `client.readFragment`, `client.watchFragment`, `useFragment`, and `useSuspenseFragment`.

  NOTE: This change does not affect the equivalent `cache.*` APIs. To read data from the cache without first running document transforms, run `cache.readQuery`, `cache.readFragment`, etc.

- [#12705](https://github.com/apollographql/apollo-client/pull/12705) [`a60f411`](https://github.com/apollographql/apollo-client/commit/a60f411e58cc67730d0dc4513e4045f004027ded) Thanks [@jerelmiller](https://github.com/jerelmiller)! - `cache-only` queries will now initialize with `loading: false` and `networkStatus: NetworkStatus.ready` when there is no data in the cache.

  This means `useQuery` will no longer render a short initial loading state before rendering `loading: false` and `ObservableQuery.getCurrentResult()` will now return `loading: false` immediately.

- [#12475](https://github.com/apollographql/apollo-client/pull/12475) [`3de63eb`](https://github.com/apollographql/apollo-client/commit/3de63ebcdf95a87adc31e6b4a39cae5391ed945a) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Unify error behavior on mutations for GraphQL errors and network errors by ensuring network errors are subject to the `errorPolicy`. Network errors created when using an `errorPolicy` of `all` will now resolve the promise and be returned on the `error` property of the result, or stripped away when the `errorPolicy` is `none`.

- [#12384](https://github.com/apollographql/apollo-client/pull/12384) [`6aa6fd3`](https://github.com/apollographql/apollo-client/commit/6aa6fd316cfdb31ebbe3e3133cca2965604e7ca1) Thanks [@jerelmiller](https://github.com/jerelmiller)! - Remove `fromError` utility function. Use [`throwError`](https://rxjs.dev/api/index/function/throwError) instead.

- [#12649](https://github.com/apollographql/apollo-client/pull/12649) [`0be92ad`](https://github.com/apollographql/apollo-client/commit/0be92ad51cf8de444fa1cc507bab2c21d230a44e) Thanks [@jerelmiller](https://github.com/jerelmiller)! - The `TData` generic provided to types that return a `dataState` property is now modified by the given `DataState` generic instead of passing a modified `TData` type. For example, a `QueryRef` that could return partial data was defined as `QueryRef<DeepPartial<TData>, TVariables>`. Now `TData` should be provided unmodified and a set of allowed states should be given instead: `QueryRef<TData, TVariables, 'complete' | 'streaming' | 'partial'>`.

  To migrate, use the following guide to replace your type with the right set of states (all types listed below are changed the same way):

  ```diff
  - QueryRef<TData, TVariables>
  // `QueryRef`'s default is 'complete' | 'streaming' so this can also be left alone if you prefer
  // All other types affected by this change default to all states
  + QueryRef<TData, TVariables>
  + QueryRef<TData, TVariables, 'complete' | 'streaming'>

  - QueryRef<TData | undefined, TVariables>
  + QueryRef<TData, TVariables, 'complete' | 'streaming' | 'empty'>

  - QueryRef<DeepPartial<TData>, TVariables>
  + QueryRef<TData, TVariables, 'complete' | 'streaming' | 'partial'>

  - QueryRef<DeepPartial<TData> | undefined, TVariables>
  + QueryRef<TData, TVariables, 'complete' | 'streaming' | 'partial' | 'empty'>
  ```

  The following types are affected. Provide the allowed `dataState` values to the `TDataState` generic:

  - `ApolloQueryResult`
  - `QueryRef`
  - `PreloadedQueryRef`
  - `useLazyQuery.Result`
  - `useQuery.Result`
  - `useReadQuery.Result`
  - `useSuspenseQuery.Result`

  All `*QueryRef` types default to `complete | streaming` states while the rest of the types default to `'complete' | 'streaming' | 'partial' | 'empty'` states. You shouldn't need to provide the states unless you need to either allow for partial data/empty values (`*QueryRef`) or a restricted set of states.

- [#12850](https://github.com/apollographql/apollo-client/pull/12850) [`268cd80`](https://github.com/apollographql/apollo-client/commit/268cd800a2d73305c0df8dd38b6bd1cee98f0fec) Thanks [@phryneas](