feat(mock): emit msw handlers and faker factories as separate files in split modes (#3730)

* feat(mock): emit msw handlers and faker factories as separate files in split modes

In split and tags-split modes the get<Op>ResponseMock factories were
duplicated in <name>.msw.ts and <name>.faker.ts. Now the faker file is
the single home of the factories and the msw file imports and re-exports
them. MSW-only output is unchanged unless the new operationResponses:
false flag is set on the msw generator entry (handlers only, undefined
fallbacks).

* fix(mock): address review feedback on import extension, uniqueBy delimiter and docs

Author: ingvaldlorentzen

docs/content/docs/reference/configuration/output.mdx

@@ -619,6 +619,7 @@ export default defineConfig({
 |--------|------|---------|-------------|
 | `type` | `'msw'` | required | Discriminator for MSW handler generation. |
 | `path` | `String` | `undefined` | Output directory for this generator's mock files. Overrides the shared `mock.path` when set. When provided in `single` or `tags` mode, mock code is written to separate files (relative to `path`) instead of being inlined into the implementation file. |
+| `operationResponses` | `Boolean` | `true` | Emit `get<Op>ResponseMock` factories in the MSW output. Set to `false` to generate handlers only, response fallbacks become `undefined`. No effect when a Faker generator also emits the factories, the handlers then import them from the `.faker` file. Honored in `split` and `tags-split` modes. |
 | `delay` | `Number \| Function \| false` | `false` | Response delay in ms. |
 | `delayFunctionLazyExecute` | `Boolean` | `false` | Execute delay function at runtime instead of at build time. |
 | `baseUrl` | `String` | `''` | Base URL for the generated MSW handlers. |
@@ -631,6 +632,8 @@ export default defineConfig({
 
 The Faker generator emits the same `get<Op>ResponseMock` factories MSW would emit, but without any `msw` dependency or HTTP handler code. Useful for tests or stories that only need fake response data.
 
+In `split` and `tags-split` modes, configuring Faker alongside MSW moves the `get<Op>ResponseMock` factories to the `.faker` file. The `.msw` file only contains the handlers and imports (and re-exports) the factories instead of duplicating them. If the Faker generator is configured with `operationResponses: false` it emits no factories, so there is nothing to move and the `.msw` file keeps them inline.
+
 | Option | Type | Default | Description |
 |--------|------|---------|-------------|
 | `type` | `'faker'` | required | Discriminator for Faker-only output. |

packages/core/src/types.ts

@@ -514,6 +514,10 @@ export interface CommonMockOptions {
 
 export interface MswMockOptions extends CommonMockOptions {
   type: typeof OutputMockType.MSW;
+  // Emit faker responses in MSW handler output, defaults to true. Disable to
+  // generate handlers only which require passing in mock responses, falls back
+  // to `undefined` if no mock response passed to handler.
+  operationResponses?: boolean;
   // Base URL prefix for the generated MSW route matchers
   baseUrl?: string;
   // Response delay before MSW handlers resolve (false disables delay)

packages/core/src/writers/generate-imports-for-builder.test.ts

@@ -199,6 +199,116 @@ describe('generateImportsForBuilder', () => {
     });
   });
 
+  describe('imports with explicit importPath', () => {
+    it('should group imports with the same importPath into a single dependency', () => {
+      const output = createMockOutput({ indexFiles: false });
+      const imports: GeneratorImport[] = [
+        {
+          name: 'getPetResponseMock',
+          values: true,
+          importPath: './pets.faker',
+        },
+        {
+          name: 'getUserResponseMock',
+          values: true,
+          importPath: './pets.faker',
+        },
+      ];
+
+      const result = generateImportsForBuilder(output, imports, '../models');
+
+      expect(result).toEqual([
+        {
+          exports: [
+            {
+              name: 'getPetResponseMock',
+              values: true,
+              importPath: './pets.faker',
+            },
+            {
+              name: 'getUserResponseMock',
+              values: true,
+              importPath: './pets.faker',
+            },
+          ],
+          dependency: './pets.faker',
+        },
+      ]);
+    });
+
+    it('should separate imports with different importPaths into different dependencies', () => {
+      const output = createMockOutput({ indexFiles: false });
+      const imports: GeneratorImport[] = [
+        {
+          name: 'getPetResponseMock',
+          values: true,
+          importPath: './pets.faker',
+        },
+        {
+          name: 'getHealthResponseMock',
+          values: true,
+          importPath: './health.faker',
+        },
+      ];
+
+      const result = generateImportsForBuilder(output, imports, '../models');
+
+      expect(result).toEqual([
+        {
+          exports: [
+            {
+              name: 'getPetResponseMock',
+              values: true,
+              importPath: './pets.faker',
+            },
+          ],
+          dependency: './pets.faker',
+        },
+        {
+          exports: [
+            {
+              name: 'getHealthResponseMock',
+              values: true,
+              importPath: './health.faker',
+            },
+          ],
+          dependency: './health.faker',
+        },
+      ]);
+    });
+
+    it('should deduplicate imports with the same name and importPath', () => {
+      const output = createMockOutput({ indexFiles: false });
+      const imports: GeneratorImport[] = [
+        {
+          name: 'getPetResponseMock',
+          values: true,
+          importPath: './pets.faker',
+        },
+        {
+          name: 'getPetResponseMock',
+          values: true,
+          importPath: './pets.faker',
+        },
+      ];
+
+      const result = generateImportsForBuilder(output, imports, '../models');
+
+      expect(result).toEqual([
+        {
+          exports: [
+            {
+              name: 'getPetResponseMock',
+              values: true,
+              importPath: './pets.faker',
+            },
+          ],
+          dependency: './pets.faker',
+        },
+      ]);
+    });
+  });
+
   describe('with importPath (package import specifier)', () => {
     it('should use package import path with indexFiles', () => {
       const output = createMockOutput({

packages/core/src/writers/generate-imports-for-builder.ts

@@ -134,17 +134,26 @@ export function generateImportsForBuilder(
     );
   }
 
-  const otherImports = uniqueBy(
+  const otherImportsMap = new Map<string, GeneratorImport[]>();
+  for (const imp of uniqueBy(
     imports.filter(
       (i): i is GeneratorImport & { importPath: string } => !!i.importPath,
     ),
-    (x) => x.name + x.importPath,
-  ).map<GeneratorDependency>((i) => {
-    return {
-      exports: [i],
-      dependency: i.importPath,
-    };
-  });
+    (x) => `${x.name}|${x.importPath}`,
+  )) {
+    const existing = otherImportsMap.get(imp.importPath);
+    if (existing) {
+      existing.push(imp);
+    } else {
+      otherImportsMap.set(imp.importPath, [imp]);
+    }
+  }
+  const otherImports = [...otherImportsMap.entries()].map<GeneratorDependency>(
+    ([dependency, exports]) => ({
+      exports,
+      dependency,
+    }),
+  );
 
   return [...schemaImports, ...schemaFactoryDeps, ...otherImports];
 }