让Babel将transpile配置文件转到CommonJS

Question

我有一个Nuxt应用程序，我想测试与Jest，我无法使它的工作。我有一个setupFilesAfterEnv属性集，其中包含一个导入翻译文件的setupTests.ts。这个翻译文件使用ES6导入/导出模块语法，但我当前的配置似乎无法对其进行转换。

babel-jest不应该通过.js属性来传输.js文件吗？

setupTests.ts

import { config } from '@vue/test-utils';
import flat from 'flat';
import '@testing-library/jest-dom/extend-expect';
import 'jest-axe/extend-expect';
import frenchTranslations from '~/config/translations/fr-FR';
...

babel.config.json

{
  "presets": ["@babel/preset-env", { "targets": { "node": "current" } }]
}

jest.config.js

module.exports = {
  moduleNameMapper: {
    '^@/(.*)$': '<rootDir>/$1',
    '^~/(.*)$': '<rootDir>/$1',
    '^vue$': 'vue/dist/vue.common.js',
  },
  moduleFileExtensions: ['ts', 'js', 'vue', 'json'],
  resolver: '<rootDir>/test/integration/resolver.js',
  transform: {
    '^.+\\.ts$': 'ts-jest',
    '^.+\\.js$': 'babel-jest',
    '^.+\\.vue$': '@vue/vue2-jest',
  },
  collectCoverage: true,
  collectCoverageFrom: [
    '<rootDir>/components/**/*.vue',
    '<rootDir>/pages/**/*.vue',
  ],
  testEnvironment: 'jsdom',
  passWithNoTests: true,
  setupFilesAfterEnv: ['<rootDir>/test/integration/setupTests.ts'],
};

/config/translations/fr-FR.js

export default {
 ...
}

Jest输出

FAIL  test/integration/components/ui/RegistrationForm.test.ts
  ● Test suite failed to run

    Jest encountered an unexpected token

    Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.

    Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.

    By default "node_modules" folder is ignored by transformers.

    Here's what you can do:
     • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
     • If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
     • To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
     • If you need a custom transformation specify a "transform" option in your config.
     • If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.

    You'll find more details and examples of these config options in the docs:
    https://jestjs.io/docs/configuration
    For information about custom transformations, see:
    https://jestjs.io/docs/code-transformation

    Details:

    /my-project/config/translations/fr-FR.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){export default {
                                                                                      ^^^^^^

    SyntaxError: Unexpected token 'export'

      1 | import { config } from '@vue/test-utils';
      2 | import flat from 'flat';
      3 | import '@testing-library/jest-dom/extend-expect';
      4 | import 'jest-axe/extend-expect';
    > 5 | import frenchTranslations from '~/config/translations/fr-FR';

      at Runtime.createScriptFromCode (node_modules/.pnpm/jest-runtime@28.1.1/node_modules/jest-runtime/build/index.js:1796:14)
      at Object.<anonymous> (test/integration/setupTests.ts:5:1)
      at TestScheduler.scheduleTests (node_modules/.pnpm/@jest+core@28.1.1/node_modules/@jest/core/build/TestScheduler.js:317:13)

----------------------|---------|----------|---------|---------|-------------------
File                  | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s
----------------------|---------|----------|---------|---------|-------------------
All files             |       0 |        0 |       0 |       0 |
 RegistrationForm.vue |       0 |        0 |       0 |       0 | 1-113
----------------------|---------|----------|---------|---------|-------------------
Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        1.35 s
Ran all test suites related to changed files.

Answer 1

尝试将setupFilesAfterEnv更改为setupFilesAfterEnv: ['@testing-library/jest-dom/extend-expect'],，并在必要时安装依赖项。

还可以尝试将babel.config.js文件更改为：

// Need to convert modules to commonjs format so Jest can undertstand them.
const isTest = String(process.env.NODE_ENV) === 'test'
const isProd = String(process.env.NODE_ENV) === 'production'

module.exports = {
    // For transformation of TSX and other react related bable plugins
    presets: [
        // Allows smart transpilation according to target environments
        ['@babel/preset-env', { modules: isTest ? 'commonjs' : false }],
        // Enabling Babel to understand TypeScript
        '@babel/preset-typescript',
    ],
}

注:如果您的代码基不在打字本中，请忽略打字本预置。

Note2:将babel.config.json改为babel.config.js也可能有帮助。