Jest encountered an unexpected token - SyntaxError: Unexpected token 'export'

Question

我正在使用 jest 来测试 React TypeScript 应用程序。

这是我的测试运行:

import { render, screen } from '@testing-library/react'
import { toBeInTheDocument } from '@testing-library/jest-dom'

import ContextProvider from '../../context/ContextProvider'
import { BrowserRouter } from 'react-router-dom'
import BlogPage from './BlogPage'

describe('BlogPage', () => {

  test('Render blog page', () => {
    render(
      <ContextProvider>
        <BrowserRouter>
          <BlogPage/>
        </BrowserRouter>
      </ContextProvider>
    )

    expect(screen.getByText('In this page you can see some of the last articles I wrote.')).toBeInTheDocument()
  })

})

这是我遇到的错误：

FAIL  src/components/blogPage/BlogPage.test.js
  ● 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:

    /home/German/Desktop/ger/code/projects/my-website/node_modules/react-markdown/index.js:6
    export {uriTransformer} from './lib/uri-transformer.js'
    ^^^^^^

    SyntaxError: Unexpected token 'export'

    > 1 | import ReactMarkdown from 'react-markdown'
        | ^
      2 | import Accordion from 'react-bootstrap/Accordion'
      3 |
      4 | interface Props {

我理解这是因为我使用的库 (react-markdown) 没有预编译的源代码。问题是我按照文档 (https://jestjs.io/docs/tutorial-react-native#transformignorepatterns-customization) 并将 react-markdown 文件夹添加到 transformIgnorePatterns 配置中，我仍然得到错误。

这是我的 jest.config.ts 文件：

import type { Config } from '@jest/types'

const config: Config.InitialOptions = {
  verbose: true,
  transform: {
    '^.+\.ts?$': 'ts-jest'
  },
  transformIgnorePatterns: [
    'node_modules/(?!react-markdown/)'
  ]
}
export default config

我试过添加 <rootDir> 就像 <rootDir>/node_modules/(?!react-markdown/) 一样，但没有任何区别。

我还尝试直接从 package.json 而不是 jest.config 文件配置 jest，但也没有什么不同。

然后我发现这个问题：Jest transformIgnorePatterns not working，其中提到你需要配置Babel。

我使用 create-react-app 创建了我的应用程序，所以我的应用程序上没有 Babel。我安装了它并创建了一个 babel.config.js 文件，我在里面放了：

module.exports = {
    "presets": [
        "@babel/preset-env"
    ]
};

但我仍然收到错误... 我运行没主意了。关于如何解决这个问题的任何线索？

可在此处找到完整代码：https://github.com/coccagerman/my-website

Answer 1

react-markdown 作为 js 发布，在你的 jest 配置中添加 babel-jest 作为转换器

  transform: {
    '^.+\.ts?$': 'ts-jest',
    "^.+\.(js|jsx)$": "babel-jest"
  },

Jest encountered an unexpected token - SyntaxError: Unexpected token 'export'

Jest encountered an unexpected token - SyntaxError: Unexpected token 'export'

javascript

testing

unit-testing

reactjs

jestjs