Jest doesn't see the default export with ESM configured - jestjs

Question

I'm using Jest with ts-jest module. I've followed the instructions on how to enalbe ESM, seems like ESM is working now. But when running tests, Jest doesn't see default export of my app, error:
SyntaxError: The requested module '../app' does not provide an export named 'default'
I've commented all tests, except the first one, now my test file looks like this:
describe("User registration", () => {
it("GET should return 404", async () => {
const res = await request(app).get("/api/register");
assert.equal(res.statusCode, 404);
});
}
app.ts:
import dotenv from "dotenv";
import express from "express";
import cors from "cors";
import cookieParser from "cookie-parser";
import fileUpload from "express-fileupload";
import router from "./router/index";
import errorMiddleware from "./middlewares/error-middleware";
dotenv.config();
const app = express();
// enable req.ip
app.set("trust proxy", true);
app.use(fileUpload());
app.use(express.json({ limit: "1000mb" }));
app.use(cookieParser());
app.use(
cors({
credentials: true,
origin: process.env.CLIENT_URL,
})
);
app.use("/api", router);
app.use(errorMiddleware);
export default app;
The only thing i tried was replacing
import app from "../app"; with import { default as app } from "../app";
Path to app.ts is correct
My tsconfig.json:
{
"compilerOptions": {
/* Language and Environment */
"target": "ES6" /* Set the JavaScript language version for emitted JavaScript and include compatible library declarations. */,
/* Modules */
"module": "ES6" /* Specify what module code is generated. */,
"rootDir": "./src" /* Specify the root folder within your source files. */,
"moduleResolution": "node" /* Specify how TypeScript looks up a file from a given module specifier. */,
"baseUrl": "./src" /* Specify the base directory to resolve non-relative module names. */,
"sourceMap": true /* Create source map files for emitted JavaScript files. */,
"outDir": "./build" /* Specify an output folder for all emitted files. */,
"esModuleInterop": true /* Emit additional JavaScript to ease support for importing CommonJS modules. This enables 'allowSyntheticDefaultImports' for type compatibility. */,
"forceConsistentCasingInFileNames": true /* Ensure that casing is correct in imports. */,
/* Type Checking */
"strict": true /* Enable all strict type-checking options. */,
"noImplicitAny": true /* Enable error reporting for expressions and declarations with an implied 'any' type. */,
"skipLibCheck": true /* Skip type checking all .d.ts files. */
}
}
Jest version: ^29.3.1
TypeScript version: 4.9.4

Answer 1

mate. Got rid of this error here. Looks like you just forgot to export the variable app... so, if everything is configured properly, adding this line to your app.ts should do the trick:
import dotenv from "dotenv";
import express from "express";
import cors from "cors";
import cookieParser from "cookie-parser";
import fileUpload from "express-fileupload";
import router from "./router/index";
import errorMiddleware from "./middlewares/error-middleware";
dotenv.config();
const app = express();
// enable req.ip
app.set("trust proxy", true);
app.use(fileUpload());
app.use(express.json({ limit: "1000mb" }));
app.use(cookieParser());
app.use(
cors({
credentials: true,
origin: process.env.CLIENT_URL,
})
);
app.use("/api", router);
app.use(errorMiddleware);
export default app; // <--- THIS LINE HERE