feat: support discriminating null and undefined within useFragment

.changeset/fresh-files-push.md

@@ -0,0 +1,19 @@
+---
+'@graphql-codegen/client-preset': minor
+---
+
+Support discriminating `null` and `undefined` within the `useFragment` function.
+
+```ts
+function MyComponent(props: FragmentType<typeof MyFragment> | null) {
+  const data = useFragment(MyFragment, props)
+  // data is `MyFragment | null`
+}
+
+function MyComponent(props: FragmentType<typeof MyFragment> | undefined) {
+  const data = useFragment(MyFragment, props)
+  // data is `MyFragment | undefined`
+}
+```
+
+Before, the returned type from `useFragment`  was always `TType | null | undefined`.

dev-test/gql-tag-operations-masking/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

dev-test/gql-tag-operations-masking/src/index.tsx

@@ -1,17 +1,17 @@
 /* eslint-disable @typescript-eslint/no-unused-vars */
 import React from 'react';
-import { gql, FragmentType, useFragment } from '../gql';
+import { graphql, FragmentType, useFragment } from '../gql';
 import { useQuery } from 'urql';
 
-const TweetFragment = gql(/* GraphQL */ `
+const TweetFragment = graphql(/* GraphQL */ `
   fragment TweetFragment on Tweet {
     id
     body
     ...TweetAuthorFragment
   }
 `);
 
-const TweetAuthorFragment = gql(/* GraphQL */ `
+const TweetAuthorFragment = graphql(/* GraphQL */ `
   fragment TweetAuthorFragment on Tweet {
     id
     author {
@@ -21,7 +21,7 @@ const TweetAuthorFragment = gql(/* GraphQL */ `
   }
 `);
 
-const TweetsFragment = gql(/* GraphQL */ `
+const TweetsFragment = graphql(/* GraphQL */ `
   fragment TweetsFragment on Query {
     Tweets {
       id
@@ -30,7 +30,7 @@ const TweetsFragment = gql(/* GraphQL */ `
   }
 `);
 
-const TweetAppQuery = gql(/* GraphQL */ `
+const TweetAppQuery = graphql(/* GraphQL */ `
   query TweetAppQuery {
     ...TweetsFragment
   }
@@ -53,7 +53,7 @@ const TweetAuthor = (props: { tweet: FragmentType<typeof TweetAuthorFragment> })
   return <div>{tweet.author?.username}</div>;
 };
 
-const Tweets = (props: { tweets: FragmentType<typeof TweetsFragment> | undefined }) => {
+const Tweets = (props: { tweets: FragmentType<typeof TweetsFragment> | null | undefined }) => {
   const tweets = useFragment(TweetsFragment, props.tweets);
 
   return <ul>{tweets?.Tweets?.map(tweet => <Tweet key={tweet.id} tweet={tweet} />) ?? null}</ul>;

dev-test/gql-tag-operations-urql/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

dev-test/gql-tag-operations/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

dev-test/gql-tag-operations/graphql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

dev-test/gql-tag-operations/src/index.ts

@@ -1,23 +1,23 @@
 /* eslint-disable @typescript-eslint/no-unused-vars */
 
-import { gql, DocumentType } from '../gql.js';
+import { graphql, DocumentType } from '../gql/gql.js';
 
-const FooQuery = gql(/* GraphQL */ `
+const FooQuery = graphql(/* GraphQL */ `
   query Foo {
     Tweets {
       id
     }
   }
 `);
 
-const LelFragment = gql(/* GraphQL */ `
+const LelFragment = graphql(/* GraphQL */ `
   fragment Lel on Tweet {
     id
     body
   }
 `);
 
-const BarQuery = gql(/* GraphQL */ `
+const BarQuery = graphql(/* GraphQL */ `
   query Bar {
     Tweets {
       ...Lel

examples/persisted-documents-string-mode/src/gql/fragment-masking.ts

@@ -16,7 +16,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/persisted-documents/src/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/react/apollo-client-defer/src/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/react/apollo-client-swc-plugin/src/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/react/apollo-client/src/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/react/http-executor/src/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/react/nextjs-swr/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/react/tanstack-react-query/src/gql/fragment-masking.ts

@@ -16,7 +16,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/react/urql/src/gql/fragment-masking.ts

@@ -16,7 +16,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/typescript-esm/src/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/typescript-graphql-request/src/gql/fragment-masking.ts

@@ -16,7 +16,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined

examples/vite/vite-react-cts/src/gql/fragment-masking.ts

@@ -17,7 +17,17 @@ export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>>
 ): TType;
+// return nullable if `fragmentType` is undefined
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | undefined
+): TType | undefined;
 // return nullable if `fragmentType` is nullable
+export function useFragment<TType>(
+  _documentNode: DocumentTypeDecoration<TType, any>,
+  fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null
+): TType | null;
+// return nullable if `fragmentType` is nullable or undefined
 export function useFragment<TType>(
   _documentNode: DocumentTypeDecoration<TType, any>,
   fragmentType: FragmentType<DocumentTypeDecoration<TType, any>> | null | undefined