Actually use ECMAScript modules

Makefile

@@ -1,3 +1,5 @@
+export NODE_OPTIONS := --experimental-vm-modules --redirect-warnings=artifacts/node-warnings
+
 -include .makefiles/Makefile
 -include .makefiles/pkg/js/v1/Makefile
 -include .makefiles/pkg/js/v1/with-yarn.mk

README.md

@@ -14,3 +14,8 @@
 // jest.config.js
 export { default } from "@snout/jest-config";
 ```
+
+```makefile
+# Makefile
+export NODE_OPTIONS := --experimental-vm-modules --redirect-warnings=artifacts/node-warnings
+```

jest.config.js

@@ -1,10 +1,21 @@
-export default {
-  preset: "es-jest",
+/** @type {import('jest').Config} */
+const config = {
+  preset: "ts-jest/presets/default-esm",
+  moduleNameMapper: {
+    "^(\\.{1,2}/.*)\\.js$": "$1",
+  },
   transform: {
-    "\\.tsx?$": "ts-jest",
+    "^.+\\.tsx?$": [
+      "ts-jest",
+      {
+        useESM: true,
+      },
+    ],
   },
-  transformIgnorePatterns: [],
-  collectCoverageFrom: ["src/**/*"],
+  testMatch: ["<rootDir>/test/**/*.spec.*"],
+  resetMocks: true,
+  collectCoverageFrom: ["<rootDir>/src/**/*"],
   coverageDirectory: "artifacts/coverage/jest",
-  testMatch: ["**/test/unit/**/*.spec.*"],
 };
+
+export default config;

package.json

@@ -19,14 +19,13 @@
     "jest.config.js"
   ],
   "dependencies": {
-    "@types/jest": "^29.0.0",
-    "es-jest": "^2.0.0",
-    "jest": "^29.0.2",
-    "ts-jest": "^29.0.1"
+    "@types/jest": "^29.2.0",
+    "jest": "^29.2.2",
+    "ts-jest": "^29.0.3"
   },
   "devDependencies": {
-    "@snout/tsconfig": "^2.0.0",
+    "@snout/tsconfig": "^3.0.0",
     "prettier": "^2.7.1",
-    "typescript": "^4.8.2"
+    "typescript": "^4.8.4"
   }
 }

test/fixture/module.ts

@@ -0,0 +1 @@
+export const foo = "foo";

test/unit/example.spec.ts

@@ -1,3 +1,5 @@
-it("should have a single test for CI to pass", () => {
-  expect(true).toBe(true);
+import { foo } from "../fixture/module.js";
+
+it("should resolve ECMAScript modules", () => {
+  expect(foo).toBe("foo");
 });