Fix #1651: moduleTypes may not be overriding module type for custom transpilers

src/index.ts

@@ -751,7 +751,9 @@ export function create(rawOptions: CreateOptions = {}): Service {
       'Transformers function is unavailable in "--transpile-only"'
     );
   }
-  let customTranspiler: Transpiler | undefined = undefined;
+  let createTranspiler:
+    | ((compilerOptions: TSCommon.CompilerOptions) => Transpiler)
+    | undefined;
   if (transpiler) {
     if (!transpileOnly)
       throw new Error(
@@ -762,11 +764,21 @@ export function create(rawOptions: CreateOptions = {}): Service {
     const transpilerOptions =
       typeof transpiler === 'string' ? {} : transpiler[1] ?? {};
     const transpilerPath = projectLocalResolveHelper(transpilerName, true);
-    const transpilerFactory: TranspilerFactory = require(transpilerPath).create;
-    customTranspiler = transpilerFactory({
-      service: { options, config, projectLocalResolveHelper },
-      ...transpilerOptions,
-    });
+    const transpilerFactory = require(transpilerPath)
+      .create as TranspilerFactory;
+    createTranspiler = function (compilerOptions) {
+      return transpilerFactory({
+        service: {
+          options,
+          config: {
+            ...config,
+            options: compilerOptions,
+          },
+          projectLocalResolveHelper,
+        },
+        ...transpilerOptions,
+      });
+    };
   }
 
   /**
@@ -1277,6 +1289,7 @@ export function create(rawOptions: CreateOptions = {}): Service {
     const compilerOptions = { ...config.options };
     if (overrideModuleType !== undefined)
       compilerOptions.module = overrideModuleType;
+    let customTranspiler = createTranspiler?.(compilerOptions);
     return (code: string, fileName: string): SourceOutput => {
       let result: _ts.TranspileOutput;
       if (customTranspiler) {

src/test/index.spec.ts

@@ -1197,39 +1197,46 @@ test.suite('ts-node', (test) => {
         expect(stdout).toBe('');
       });
 
-      async function runModuleTypeTest(project: string, ext: string) {
-        const { err, stderr, stdout } = await exec(
-          `${CMD_ESM_LOADER_WITHOUT_PROJECT} ./module-types/${project}/test.${ext}`,
-          {
-            env: {
-              ...process.env,
-              TS_NODE_PROJECT: `./module-types/${project}/tsconfig.json`,
-            },
-          }
-        );
-        expect(err).toBe(null);
-        expect(stdout).toBe(`Failures: 0\n`);
-      }
-
-      test('moduleTypes should allow importing CJS in an otherwise ESM project', async (t) => {
-        // A notable case where you can use ts-node's CommonJS loader, not the ESM loader, in an ESM project:
-        // when loading a webpack.config.ts or similar config
-        const { err, stderr, stdout } = await exec(
-          `${CMD_TS_NODE_WITHOUT_PROJECT_FLAG} --project ./module-types/override-to-cjs/tsconfig.json ./module-types/override-to-cjs/test-webpack-config.cjs`
-        );
-        expect(err).toBe(null);
-        expect(stdout).toBe(``);
-
-        await runModuleTypeTest('override-to-cjs', 'cjs');
-        if (semver.gte(process.version, '14.13.1'))
-          await runModuleTypeTest('override-to-cjs', 'mjs');
-      });
-
-      test('moduleTypes should allow importing ESM in an otherwise CJS project', async (t) => {
-        await runModuleTypeTest('override-to-esm', 'cjs');
-        // Node 14.13.0 has a bug(?) where it checks for ESM-only syntax *before* we transform the code.
-        if (semver.gte(process.version, '14.13.1'))
-          await runModuleTypeTest('override-to-esm', 'mjs');
+      test.suite('moduleTypes', (test) => {
+        suite('with vanilla ts transpilation', 'tsconfig.json');
+        suite('with third-party-transpiler', 'tsconfig-swc.json');
+        function suite(name: string, tsconfig: string) {
+          test.suite(name, (test) => {
+            test('supports CJS webpack.config.ts in an otherwise ESM project', async (t) => {
+              // A notable case where you can use ts-node's CommonJS loader, not the ESM loader, in an ESM project:
+              // when loading a webpack.config.ts or similar config
+              const { err, stdout } = await exec(
+                `${CMD_TS_NODE_WITHOUT_PROJECT_FLAG} --project ./module-types/override-to-cjs/${tsconfig} ./module-types/override-to-cjs/test-webpack-config.cjs`
+              );
+              expect(err).toBe(null);
+              expect(stdout).toBe(``);
+            });
+            test('should allow importing CJS in an otherwise ESM project', async (t) => {
+              await run('override-to-cjs', tsconfig, 'cjs');
+              if (semver.gte(process.version, '14.13.1'))
+                await run('override-to-cjs', tsconfig, 'mjs');
+            });
+            test('should allow importing ESM in an otherwise CJS project', async (t) => {
+              await run('override-to-esm', tsconfig, 'cjs');
+              // Node 14.13.0 has a bug(?) where it checks for ESM-only syntax *before* we transform the code.
+              if (semver.gte(process.version, '14.13.1'))
+                await run('override-to-esm', tsconfig, 'mjs');
+            });
+          });
+        }
+        async function run(project: string, config: string, ext: string) {
+          const { err, stderr, stdout } = await exec(
+            `${CMD_ESM_LOADER_WITHOUT_PROJECT} ./module-types/${project}/test.${ext}`,
+            {
+              env: {
+                ...process.env,
+                TS_NODE_PROJECT: `./module-types/${project}/${config}`,
+              },
+            }
+          );
+          expect(err).toBe(null);
+          expect(stdout).toBe(`Failures: 0\n`);
+        }
       });
     }
 

tests/module-types/override-to-cjs/tsconfig-swc.json

@@ -0,0 +1,15 @@
+{
+  "ts-node": {
+    "swc": true,
+    "moduleTypes": {
+      "webpack.config.ts": "cjs",
+      // Test that subsequent patterns override earlier ones
+      "src/cjs-subdir/**/*": "esm",
+      "src/cjs-subdir": "cjs",
+      "src/cjs-subdir/esm-exception.ts": "esm"
+    }
+  },
+  "compilerOptions": {
+    "module": "ES2015"
+  }
+}

tests/module-types/override-to-esm/tsconfig-swc.json

@@ -0,0 +1,14 @@
+{
+  "ts-node": {
+    "swc": true,
+    "moduleTypes": {
+      // Test that subsequent patterns override earlier ones
+      "src/esm-subdir/**/*": "cjs",
+      "src/esm-subdir": "esm",
+      "src/esm-subdir/cjs-exception.ts": "cjs"
+    }
+  },
+  "compilerOptions": {
+    "module": "CommonJS"
+  }
+}