globalSetup doesn't process styleMocks / moduleNameMappers

[mschipperheyn]

🐛 Bug Report

globalSetup does not work with moduleNameMappers. In most setups this would be ok, but there are situations such as SSR where you want to setup a server once, you can run into issues with this.

Related to: #5164

To Reproduce

• Set up a styleMock and a globalSetup file
• import a React component that imports a stylesheet in a globalSetup file

Expected behavior

globalSetup processes moduleNameMappers. The idea that globalSetup runs before "everything" is not practical. Setup will generally require some configuration options for things to work.

Run npx envinfo --preset jest

Paste the results here:

  System:
    OS: macOS Sierra 10.12.6
    CPU: x64 Intel(R) Core(TM) i7-3615QM CPU @ 2.30GHz
  Binaries:
    Node: 8.9.4 - ~/.nvm/versions/node/v8.9.4/bin/node
    Yarn: 1.5.1 - /usr/local/bin/yarn
    npm: 6.0.0 - /Users/Shared/java/projects/react/projects/mobile-minds/node_modules/.bin/npm
  npmPackages:
    jest: 22.4.3 => 22.4.3 

The workaround I currently use for both this issue and the related babel-transpile issue:

require('babel-register');
require('babel-polyfill');
['.css', '.eot', '.woff', '.ttf'].forEach(ext => {
  require.extensions[ext] = () => ({});
});

['.svg', '.png', '.jpg'].forEach(ext => {
  require.extensions[ext] = () => '';
});

[alexk111]

Any updates on this issue?

[rickhanlonii]

This seems like a feature request, can you post a full example of the bug?

[Akryum]

Here is a runnable reproduction of the bug:

https://codesandbox.io/s/boring-wilbur-ibkmj

Reproduction steps

1 - Un-comment globalSetup line in jest.config.js:

globalSetup: './tests/globalSetup.js'

2 - Run the following in the terminal:

yarn test

Error output:

Error: Cannot find module '@/utils'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:636:15)
    at Function.Module._load (internal/modules/cjs/loader.js:562:25)
    at Module.require (internal/modules/cjs/loader.js:690:17)
    at require (internal/modules/cjs/helpers.js:25:18)
    at Object.<anonymous> (/sandbox/tests/globalSetup.js:3:5)
    at Module._compile (internal/modules/cjs/loader.js:776:30)
    at Module._compile (/sandbox/node_modules/pirates/lib/index.js:99:24)
    at Module._extensions..js (internal/modules/cjs/loader.js:787:10)
    at Object.newLoader [as .js] (/sandbox/node_modules/pirates/lib/index.js:104:7)
    at Module.load (internal/modules/cjs/loader.js:653:32)

[stnwk]

Hi everyone! friendly ping

@rickhanlonii @SimenB

This seems like a feature request, can you post a full example of the bug?

I have to disagree. I don't think this is a feature request but rather a bug:
The moduleNameMapper configuration is correctly respected in all setupFilesAfterEnv and setupFiles for example. globalSetup and globalTeardown surprisingly don't respect that :/

Reproduction on latest jest version

I prepared a simple reproduction on the latest jest version 25.2.7, see https://codesandbox.io/s/jest-globalsetup-modulenamemapper-bug-g1ol7 and the README.

This is currently preventing us from speeding up our test setup substantially, because we cannot re-use a service for all tests and instead have to re-create it for every test file by putting it in a setupFiles entry. We'd love to see this fixed, let me know if I can be of any more help!

Thank you :)

[rickhanlonii]

Thanks for the repro cases, I agree this is a bug now (or a feature request to change the behavior, however you want to look at it). If anyone wants to submit a PR to fix it I'm happy to review!

[stnwk]

If anyone wants to submit a PR to fix it I'm happy to review!

@rickhanlonii I'm happy to take a look at it. Do you have any recommendations into where I might start looking as a first-time contributor? Thanks!

[rickhanlonii]

@stnwk I do not - I would grep for setupFilesAfterEnv and track down how it uses moduleNameMapper, and then grep for globalSetup to see why it doesn't use it. Let me know if you have any questions 👍

[wanton7]

I had to do my own monkey patching of require in globalSetup to make tsconfig "paths" work. I hope this code helps someone else. I run this code top of global setup JavaScript file. It doesn't support all kinds of paths supported in tsconfig but works in cases we have.

const Mod = require('module');
const { compilerOptions } = require('../../tsconfig');
var path = require('path');

const currentDir = process.cwd();

const req = Mod.prototype.require;

Mod.prototype.require = function () {
  const modulePath = arguments[0];
  for (const fromPath of Object.keys(compilerOptions.paths)) {
    let toPath = compilerOptions.paths[fromPath][0];
    if (!fromPath || !fromPath.endsWith('/*') || !toPath || !toPath.endsWith('/*')) {
      throw Error('Only /* suffix supported');
    }
    if (!toPath.startsWith('./')) throw Error('Only destination prefix ./ supported');

    if (modulePath.startsWith(fromPath.slice(0, -1))) {
      arguments[0] = path.join(currentDir, toPath.slice(2, -1), modulePath.slice(fromPath.length - 1));
    }
  }

  return req.apply(this, arguments);
};

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