How to use a Global Variable in Jest

Question

I've got my Yarn package.json set up like this, where I create a global variable called localPath.

{
  "jest": {
    "globals": {
      "localPath": "Users/alex/Git/mytodolist"
    }
  }
}

Then, in one of my spec tests, I run

console.log(localPath)

but get this error.

ReferenceError: localPath is not defined

      5 | 
    > 6 |   console.log(localPath)

Does anyone know how to call the global variable you set up? I can only find articles on creating the variable, but not on how to call it.

Source: https://jestjs.io/docs/en/configuration#globals-object

Edit: Thanks to @slideshowp2 for the correct answer below. Turns out I didn't need to use a global variable in the end, as you can dynamically grab the execution path at run time. However, this will certainly be useful in the future.

beforeAll(async () => {
  await page.goto('file:///'+process.cwd()+'/index.html')
})

Answer 1

It should work. Here is a minimal working example:

./src/index.js:

export function sum(a, b) {
  return a + b;
}

./src/__tests__/index.spec.js:

import { sum } from "../";

it("should sum", () => {
  // eslint-disable-next-line
  console.log("localPath: ", localPath);
  const actualValue = sum(1, 2);
  expect(actualValue).toBe(3);
});

jest.config.js:

module.exports = {
  preset: "ts-jest/presets/js-with-ts",
  testEnvironment: "node",
  coverageReporters: ["json", "text", "lcov", "clover"],
  testMatch: ["**/__tests__/**/*.[jt]s?(x)", "**/?(*.)+(spec|test).[jt]s?(x)"],
  globals: {
    localPath: "Users/alex/Git/mytodolist"
  }
};

Unit test result:

 PASS  src/__tests__/index.spec.js
  ✓ should sum (4ms)

  console.log src/__tests__/index.spec.js:5
    localPath:  Users/alex/Git/mytodolist

Test Suites: 1 passed, 1 total
Tests:       1 passed, 1 total
Snapshots:   0 total
Time:        2.233s
Ran all test suites.

As you can see, the value of global variable localPath has been set. Please print the global object and check in your tests.

Codesandbox: https://codesandbox.io/s/unruffled-feistel-byfcc