Only generate Exact utility type if documents have operations

.changeset/khaki-clubs-say.md

@@ -0,0 +1,9 @@
+---
+'@graphql-codegen/typescript-operations': patch
+---
+
+Only generate `Exact` utility type at the top if it is used
+
+`Exact` utility is only used to wrap variables types for operations (queries, mutations and subscriptions) if they exist in the document. `Exact` is never used when there are _only_ fragments.
+
+This is important to conditionally generate as users may use very strict tsconfig that will fail compiling if there are unused types.

dev-test/star-wars/types.d.ts

@@ -1,2 +1 @@
-type Exact<T extends { [key: string]: unknown }> = { [K in keyof T]: T[K] };
 export type Incremental<T> = T | { [P in keyof T]?: P extends ' $fragmentName' | '__typename' ? T[P] : never };

packages/plugins/typescript/operations/src/visitor.ts

@@ -73,6 +73,7 @@ export class TypeScriptDocumentsVisitor extends BaseDocumentsVisitor<
   TypeScriptDocumentsParsedConfig
 > {
   protected _usedNamedInputTypes: UsedNamedInputTypes = {};
+  protected _needsExactUtilityType: boolean = false;
   private _outputPath: string;
 
   constructor(
@@ -386,7 +387,7 @@ export class TypeScriptDocumentsVisitor extends BaseDocumentsVisitor<
 
   protected applyVariablesWrapper(variablesBlock: string, operationType: string): string {
     const extraType = this.config.allowUndefinedQueryVariables && operationType === 'Query' ? ' | undefined' : '';
-
+    this._needsExactUtilityType = true;
     return `Exact<${variablesBlock === '{}' ? `{ [key: string]: never; }` : variablesBlock}>${extraType}`;
   }
 
@@ -501,7 +502,10 @@ export class TypeScriptDocumentsVisitor extends BaseDocumentsVisitor<
   }
 
   getExactUtilityType(): string | null {
-    if (!this.config.generatesOperationTypes) {
+    if (
+      !this.config.generatesOperationTypes || // 1. If we don't generate operation types, definitely do not need `Exact`
+      !this._needsExactUtilityType // 2. Even if we generate operation types, we may not need `Exact` if there's no operations in the documents i.e. only fragments found
+    ) {
       return null;
     }
 

packages/plugins/typescript/operations/tests/ts-documents.standalone.spec.ts

@@ -11,6 +11,14 @@ describe('TypeScript Operations Plugin - Standalone', () => {
         users(input: UsersInput!): UsersResponse!
       }
 
+      type Mutation {
+        makeUserAdmin(id: ID!): User!
+      }
+
+      type Subscription {
+        userChanges(id: ID!): User!
+      }
+
       type ResponseError {
         error: ResponseErrorType!
       }
@@ -90,6 +98,23 @@ describe('TypeScript Operations Plugin - Standalone', () => {
           }
         }
       }
+
+      mutation MakeAdmin {
+        makeUserAdmin(id: "100") {
+          ...UserFragment
+        }
+      }
+
+      subscription UserChanges {
+        makeUserAdmin(id: "100") {
+          ...UserFragment
+        }
+      }
+
+      fragment UserFragment on User {
+        id
+        role
+      }
     `);
 
     const result = mergeOutputs([await plugin(schema, [{ document }], {}, { outputFile: '' })]);
@@ -147,6 +172,18 @@ describe('TypeScript Operations Plugin - Standalone', () => {
           | { result: Array<{ __typename: 'User' }> }
           | { __typename: 'ResponseError' }
          };
+
+      export type MakeAdminMutationVariables = Exact<{ [key: string]: never; }>;
+
+
+      export type MakeAdminMutation = { makeUserAdmin: { id: string, role: UserRole } };
+
+      export type UserChangesSubscriptionVariables = Exact<{ [key: string]: never; }>;
+
+
+      export type UserChangesSubscription = Record<PropertyKey, never>;
+
+      export type UserFragmentFragment = { id: string, role: UserRole };
       "
     `);
 
@@ -712,17 +749,6 @@ describe('TypeScript Operations Plugin - Standalone', () => {
         user(id: ID!): User
       }
 
-      type ResponseError {
-        error: ResponseErrorType!
-      }
-
-      enum ResponseErrorType {
-        NOT_FOUND
-        INPUT_VALIDATION_ERROR
-        FORBIDDEN_ERROR
-        UNEXPECTED_ERROR
-      }
-
       type User {
         id: ID!
         name: String!
@@ -782,4 +808,45 @@ describe('TypeScript Operations Plugin - Standalone', () => {
 
     validateTs(result, undefined, undefined, undefined, undefined, true);
   });
+
+  it('does not generate Exact utility type if there are only fragments', async () => {
+    const schema = buildSchema(/* GraphQL */ `
+      type Query {
+        user(id: ID!): User
+      }
+
+      type User {
+        id: ID!
+        name: String!
+        role: UserRole!
+        createdAt: DateTime!
+        bestFriend: User
+        goodFriends: [User!]!
+      }
+
+      enum UserRole {
+        ADMIN
+        CUSTOMER
+      }
+
+      scalar DateTime
+    `);
+    const document = parse(/* GraphQL */ `
+      fragment UserPart on User {
+        id
+        name
+      }
+    `);
+
+    const result = mergeOutputs([await plugin(schema, [{ document }], {}, { outputFile: '' })]);
+
+    expect(result).toMatchInlineSnapshot(`
+      "
+      export type Incremental<T> = T | { [P in keyof T]?: P extends ' $fragmentName' | '__typename' ? T[P] : never };
+      export type UserPartFragment = { id: string, name: string };
+      "
+    `);
+
+    validateTs(result, undefined, undefined, undefined, undefined, true);
+  });
 });

packages/presets/client/tests/client-preset.enum.spec.ts

@@ -23,7 +23,6 @@ describe('client-preset - Enum', () => {
     const graphqlFile = result.find(file => file.filename === 'out1/graphql.ts');
     expect(graphqlFile.content).toMatchInlineSnapshot(`
       "/* eslint-disable */
-      type Exact<T extends { [key: string]: unknown }> = { [K in keyof T]: T[K] };
       export type Incremental<T> = T | { [P in keyof T]?: P extends ' $fragmentName' | '__typename' ? T[P] : never };"
     `);
   });