Multiple Jest projects bleed module file extension resolution between environments

Do you want to request a feature or report a bug?

Bug

What is the current behavior?

I’ve created a test-case repo that illustrates this behavior: paularmstrong/jest-project-bleed.

---

In some cases, we want to have code that is defined differently for a node.js environment than a browser/DOM environment. We do this to avoid needing to polyfill node.js’s url module in the browser when we already have access to a powerful window.URL API in a browser (which is not available in node.js).

To do this, we set up our build environment to build server-side code with moduleFileExtensions to resolve *.node.js files before *.js files.

In Jest, we create two separate project configurations: config/jest/node.js and config/jest/web.js. These run the tests in the appropriate environment (node and jsdom, respectively).

If the current behavior is a bug, please provide the steps to reproduce and either a repl.it demo through https://repl.it/languages/jest or a minimal repository on GitHub that we can yarn install and yarn test.

I’ve created a test-case repo that illustrates this behavior: paularmstrong/jest-project-bleed.

What is the expected behavior?

I expect all tests to pass, given their environment and correct module file resolution.

Please provide your exact Jest configuration and mention your Jest, node, yarn/npm version and operating system.

Please see the repo test case: paularmstrong/jest-project-bleed.

• yarn 0.27.5
• node 8.9.0

  "devDependencies": {
    "babel-core": "^6.26.0",
    "babel-jest": "^22.2.2",
    "babel-preset-env": "^1.6.1",
    "jest": "^22.3.0"
  },

[cbelsole]

I was able to repro this bug and I noticed when I printed out the project configs that they had the same md5 hash name which is what jest uses to pick out the right resolver. I found that in the normalizer if the name is not set it will set a name.

After fiddling around with the normalizer I came up with this code:

const normalizeMissingOptions = (options: InitialOptions): InitialOptions => {
  if (!options.name) {
    options.name = crypto
      .createHash('md5')
      .update(options.rootDir)
      .digest('hex');
  }

  options.projects = (options.projects || []).map(project => {
    if (!project.name) {
      project.name =
        crypto
          .createHash('md5')
          .update(project.rootDir)
          .digest('hex') || '';
    }
    return project;
  });

  if (!options.setupFiles) {
    options.setupFiles = [];
  }

  return options;
};

Now if the names on the projects were not set they would have their own unique name. This fixed the error since by having a unique name the right resolver was chosen.

[cpojer]

Yeah that’s a bug.