jest/ts/ tests Cannot find name 'x'

Question

I've read a ton of the previous SO questions regarding this however, none seems to solve any of my problems.

index.test.ts

import request from 'supertest';
import * as server from '../server';
import 'jest'

//close server after each request
afterEach( //cannot find name 'afterEach'
  async (): Promise<void> => {
    await server.close(); // Property 'close' does not exist on type 'typeof import(<path to file)'
  },
);

describe('get /', (): void => { //Cannot find name 'describe'. Do you need to install type definitions for a test runner? Try `npm i @types/jest` or `npm i @types/mocha`
  it('should respond as expected', async (): Promise<void> => {// cannot find 'it'...
    const response = await request(server).get('/');
    expect(response.status).toEqual(200); // cannot find 'expect'
    expect(response.body.data).toEqual('Sending some JSON'); // cannot find 'expect'...
  });
});

I have installed both jest and mocha types, just to make sure that it wasn't registering one over the other. Pretty much everything is not being recognized, .babelrcc

{
  "presets": ["@babel/preset-typescript"]
}

jest.config.js

module.exports = {
  preset: 'ts-jest',
  testEnvironment: 'node',
  transform: {
    '^.+\\.tsx?$': 'ts-jest',
  },
};

tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "target": "es6",
    "noImplicitAny": true,
    "preserveConstEnums": true,
    "outDir": "./dist",
    "sourceMap": true,
    "esModuleInterop": true
  },
  "include": ["./src/**/*"],
  "exclude": ["test", "**/*/spec.ts", "**/*/test.ts"]
}

server

import * as dotenv from 'dotenv';
dotenv.config();
import Koa from 'koa';
import logger from 'koa-logger';
import apiRoutes from './Routes';
import cors from '@koa/cors';
import bodyParser from 'koa-bodyparser';
const app = new Koa();
const PORT = process.env.PORT || 3001;
const ENV = process.env.NODE_ENV || 'Development';

app.use(logger());
app.use(cors());
app.use(bodyParser());
app.use(apiRoutes);

export const server = app.listen(PORT, (): void => {
  console.log(`🌍 Server listening on port ${PORT} - ${ENV} environment`);
});

I don't know what other information is relevant if there is something else I am missing I will update this with the information

Answer 1

You are exporting the named variable server directly while you are trying to import it as if it were the default export.

Just change it to import { server } from './server'; in index.test.ts and it will work as expected. You can also change the export to export default server in server.ts but I tend to avoid that based on this article .

Read more about export on MDN .