Preserve imports when needed in Jest integration

integration-test/integration-tests.ts

@@ -43,14 +43,14 @@ describe("integration tests", () => {
       const testConfig = await readJSONFileContentsIfExists("./test.json");
       if (testConfig?.expectedError) {
         try {
-          await execPromise(`npx jest`);
+          await execPromise(`NODE_OPTIONS=--experimental-vm-modules npx jest --no-cache`);
           assert.fail("Expected Jest to fail");
         } catch (e) {
           assert((e as {stderr: string}).stderr.includes(testConfig.expectedError));
         }
       } else {
         // Should not crash.
-        await execPromise(`npx jest`);
+        await execPromise(`NODE_OPTIONS=--experimental-vm-modules npx jest --no-cache`);
       }
     });
   }

integration-test/test-cases/jest-cases/allows-dynamic-import-of-esm-from-cjs/jest.config.js

@@ -0,0 +1,3 @@
+export default {
+  transform: {"\\.ts$": "@sucrase/jest-plugin"},
+};

integration-test/test-cases/jest-cases/allows-dynamic-import-of-esm-from-cjs/main.js

@@ -0,0 +1,2 @@
+// This file isn't transpiled, so it remains ESM at runtime.
+export const one = 1;

integration-test/test-cases/jest-cases/allows-dynamic-import-of-esm-from-cjs/main.test.ts

@@ -0,0 +1,8 @@
+test("addition", async () => {
+  // Assert that module is defined to confirm that this is a CJS file.
+  expect(module).toBeTruthy();
+
+  // This dynamic import should be preserved, not transformed to require.
+  const {one} = await import("./main");
+  expect(one + one).toBe(2 as number);
+});

integration-test/test-cases/jest-cases/allows-dynamic-import-of-esm-from-cjs/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}

integration-test/test-cases/jest-cases/preserves-imports-in-esm-mode/jest.config.js

@@ -0,0 +1,4 @@
+export default {
+  transform: {"\\.ts$": "@sucrase/jest-plugin"},
+  extensionsToTreatAsEsm: ['.ts'],
+};

integration-test/test-cases/jest-cases/preserves-imports-in-esm-mode/main.js

@@ -0,0 +1,2 @@
+// This file isn't transpiled, so it remains ESM at runtime.
+export const one = 1;

integration-test/test-cases/jest-cases/preserves-imports-in-esm-mode/main.test.ts

@@ -0,0 +1,6 @@
+// This static import should be preserved rather than transformed to require.
+import {one} from "./main";
+
+test("addition", () => {
+  expect(one + one).toBe(2 as number);
+});

integration-test/test-cases/jest-cases/preserves-imports-in-esm-mode/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "module"
+}

integrations/jest-plugin/src/index.ts

@@ -1,15 +1,18 @@
 import type {TransformOptions} from "@jest/transform";
+import {extname} from "path";
 import {Transform, transform} from "sucrase";
 
 import type {Options} from "../../../src/Options";
 
-function getTransforms(filename: string): Array<Transform> | null {
-  if (filename.endsWith(".js") || filename.endsWith(".jsx")) {
-    return ["flow", "jsx", "imports", "jest"];
-  } else if (filename.endsWith(".ts")) {
-    return ["typescript", "imports", "jest"];
-  } else if (filename.endsWith(".tsx")) {
-    return ["typescript", "jsx", "imports", "jest"];
+function getTransforms(filename: string, supportsStaticESM: boolean): Array<Transform> | null {
+  const extension = extname(filename);
+  const maybeImports: Array<Transform> = supportsStaticESM ? [] : ["imports"];
+  if ([".js", ".jsx", ".mjs", ".cjs"].includes(extension)) {
+    return [...maybeImports, "flow", "jsx", "jest"];
+  } else if (extension === ".ts") {
+    return [...maybeImports, "typescript", "jest"];
+  } else if ([".tsx", ".mts", ".cts"].includes(extension)) {
+    return [...maybeImports, "typescript", "jsx", "jest"];
   }
   return null;
 }
@@ -23,10 +26,11 @@ export function process(
   filename: string,
   options: TransformOptions<Partial<Options>>,
 ): {code: string; map?: RawSourceMap | string | null} {
-  const transforms = getTransforms(filename);
+  const transforms = getTransforms(filename, options.supportsStaticESM);
   if (transforms !== null) {
     const {code, sourceMap} = transform(src, {
       transforms,
+      preserveDynamicImport: options.supportsDynamicImport,
       ...options.transformerConfig,
       sourceMapOptions: {compiledFilename: filename},
       filePath: filename,