Custom Environments with TypeScript

[stangerjm]

I have checked the troubleshooting guide, it does not solve this issue.

Issue :

When creating a custom environment in TypeScript, Jest throws an error complaining about the TypeScript syntax. It appears that the custom environment is not being compiled.

Expected behavior :

FAIL  tests/ticket-search/advanced-search.spec.ts
  ● Test suite failed to run
      custom-environment.ts:9
          async setup(): Promise<void> {
                       ^
          SyntaxError: Unexpected token ':'
              at node_modules/jest-runner/build/runTest.js:259:7

Debug log:

log file content

N/A

jest.config.js

module.exports = {
  preset: 'ts-jest',
  testMatch: [
    '<rootDir>/tests/**/*.spec.ts',
  ],
  testRunner: 'jest-circus/runner',
  testEnvironment: './scripts/custom-environment.ts',
  moduleDirectories: [
    '.',
    './node_modules',
    './utils',
    './interfaces',
  ],
...
};

Minimal repo

https://github.com/stangerjm/ts-jest-custom-env

npm install
npx jest

[ahnpnl]

hi, this issue doesn't belong to ts-jest scope. You should check with jest team whether or not they support custom environment with ts. If they support it and pass it to transformer, ts-jest will then can handle it.

I would suggest you to open the issue for jest team.

[ahnpnl]

tag @SimenB has jest already taken into account of this feature ?

[SimenB]

It will be supported in Jest 26: jestjs/jest#8751

[stangerjm]

This is fantastic, thanks for pointing this out!

[fsevenm]

It will be supported in Jest 26: facebook/jest#8751

I don't know what did you mean it will be supported. I am using jest 26.6.1 but still getting this error

 FAIL  tests/topup-package/topup-package.spec.ts
  ● Test suite failed to run

    /home/fsevenm/nodejs-projects/deliverit/tests/test-environment.ts:1
    import NodeEnvironment from "jest-environment-node";
    ^^^^^^

    SyntaxError: Cannot use import statement outside a module

      at runTestInternal (node_modules/jest-runner/build/runTest.js:223:5)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        0.025 s

// test-environment.ts
import NodeEnvironment from "jest-environment-node";
import { createUser, destroyUsers } from "./utils";

class TestEnvironment extends NodeEnvironment {
  async setup(): Promise<void> {
    await super.setup();
    const { token } = await createUser();

    this.global.authToken = token;
  }

  async teardown(): Promise<void> {
    await destroyUsers();
    await super.teardown();
  }
}

export default TestEnvironment;

// jest.config.js
module.exports = {
  preset: "ts-jest",
  testEnvironment: "<rootDir>/tests/test-environment.ts",
  moduleNameMapper: {
    "@src/(.*)$": "<rootDir>/src/$1",
  },
  testPathIgnorePatterns: ["/node_modules/", "<rootDir>/build/"],
  globalTeardown: "<rootDir>/tests/teardown.ts",
};

[SimenB]

it didn't land in 26, but it will be in v27 (you can test it by installing jest@next)

[apgapg]

This doesn't work. as it starts throwing Cannot use import statement outside a module.
Because testEnvironment is missing in config hence i dont think its wise to use environment with js config. This shall work only with jest.config.ts

[apgapg]

Because jest@27 is already released hence this issue should be reopened

[ahnpnl]

If Jest doesn’t pass it to ts-jest, ts-jest cannot compile. I’d suggest you to debug and check first if Jest does correctly.

[apgapg]

@ahnpnl Okay let me check with jest alone

[apgapg]

Here is my jest.config.ts

// jest.config.ts
import type { InitialOptionsTsJest } from "ts-jest/dist/types";

const config: InitialOptionsTsJest = {
  // testEnvironment: "./tests/my-environment.ts",
  preset: "ts-jest",
  testPathIgnorePatterns: ["dist"],
  globalSetup: "./tests/setup.ts",
  globalTeardown: "./tests/global.teardown.ts",
  testTimeout: 30000,
  globals: {
    "ts-jest": {},
  },
};
export default config;

The above code works fine.
As soon as I try to uncomment testEnvironment and comment globalSetup, globalTeardown, Error starts occuring saying
Cannot use import statement outside a module

Here is my my-environment.ts

import NodeEnvironment from "jest-environment-node";
import { closeDbConnection, initDbConnection } from "../src/db/dbConnector";
import request from "supertest";
import app from "../src/app/app";

const idToken =<my-token>

class CustomEnvironment extends NodeEnvironment {
  async setup(): Promise<void> {
    await initDbConnection(() => {
      throw new Error("Database connection error, please try again later");
    }, null);
    const response = await request(app).get(`/api/v1/login/exchangeToken?idToken=${idToken}`);
    process.env.cookie = response.headers["set-cookie"];
    return super.setup();
  }

  async teardown() {
    await closeDbConnection();
    await super.teardown();
  }
}

module.exports = CustomEnvironment;

This error links to my code in src folder. Looks like there is some ts issue when accessing src code.
Am I missing something here?

[ahnpnl]

I could see the my-environment.ts is landed on ts-jest while debugging.

// my-environment.ts
import type {Config} from '@jest/types';
import NodeEnvironment from 'jest-environment-node';

export default class CustomEnvironment extends NodeEnvironment {
  constructor(config: Config.ProjectConfig) {
    super(config);
    this.global.one = 1;
  }
}

// jest.config.js
module.exports = {
  testEnvironment: "<rootDir>/my-environment.ts",
  preset: "ts-jest",
};

One note is: you need to set TypeScript target: ES2015, target: ES5 will throw error

TypeError: Class constructor NodeEnvironment cannot be invoked without 'new'



      at new CustomEnvironment (my-environment.ts:24:28)

Looking at your files, I don't see anything strange, not sure why it doesn't work for your case.

You can check out my repo example here https://github.com/ahnpnl/ts-jest-only-example

[ciclentfort]

I ran into the same problem. I noticed that jest-environment-node exports an actual class (like uses the class-keyword in the package in node_modules), running the testEnvironment file through ts-jest turns the "CustomEnvironment" into a function.