javascript - MUI5 无法使用 jest - SyntaxError : Cannot use import statement outside a module

Question

可重现的 repo :https://github.com/hutber/cannotusestatement

更让人担心的是:https://codesandbox.io/s/vigilant-bartik-bmz8x在沙箱中，测试通过。但是，如果您检查上面导入到此沙箱中的 repo 协议(protocol)，它将不会在本地通过。

我毫不怀疑问题是我的 Jest 没有编译运行我的测试所需的 node_modules。但我现在不知道如何让它工作。

我只是希望能够运行测试。它们目前不运行

测试

import React from 'react'
import { renderWithThemeProvider, screen } from 'test-utils'
import { Select } from './Select'

it('renders correctly', () => {
  const tree = renderWithThemeProvider(<Select id="testSelect"></Select>)
  expect(tree).toMatchSnapshot()
})

jest.config.js

module.exports = {
  roots: ['<rootDir>', './src'],
  moduleDirectories: ['<rootDir>', 'node_modules/', './src'],
  transform: {
    '^.+\\.(ts|tsx)$': 'ts-jest',
  },
  testEnvironment: 'jsdom',
  testMatch: ['**/*.test.(ts|tsx)', '**/__tests__/*.(ts|tsx)'],
  moduleNameMapper: {
    // Mocks out all these file formats when tests are run
    '\\.(jpg|ico|jpeg|png|gif|eot|otf|webp|svg|ttf|woff|woff2|mp4|webm|wav|mp3|m4a|aac|oga)$': 'identity-obj-proxy',
    '\\.(css|less|scss|sass)$': 'identity-obj-proxy',
    'app-config': '<rootDir>/app-config/default',
    '^@components(.*)$': '<rootDir>/src/components$1',
    '^@themes(.*)$': '<rootDir>/src/themes$1',
  },
  coverageThreshold: {
    global: {
      statements: 50,
    },
  },
}

babel.config.js

module.exports = {
  presets: ['@babel/preset-env', '@babel/preset-react'],
  env: {
    test: {
      presets: ['@babel/preset-env', '@babel/preset-react'],
      plugins: [
        [
        'babel-plugin-transform-imports',
        '@babel/plugin-proposal-class-properties',
        'transform-es2015-modules-commonjs',
        'babel-plugin-dynamic-import-node',
        'babel-plugin-styled-components',
      ],
    },
  },
}

package.json

"test": "jest --watchAll=false",

yarn 测试

(base) hutber@hutber:/var/www/target/component-library$ yarn test src/components/Select/Select.test.tsx
yarn run v1.22.17
$ jest --watchAll=false src/components/Select/Select.test.tsx
 FAIL  src/components/Select/Select.test.tsx
  ● 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:

    /var/www/target/component-library/node_modules/@mui/material/styles/styled.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import { createStyled, shouldForwardProp } from '@mui/system';
                                                                                      ^^^^^^

    SyntaxError: Cannot use import statement outside a module

      1 | import React from 'react'
    > 2 | import styled from '@mui/material/styles/styled'
        | ^
      3 |
      4 | import MuiSelect, { SelectProps as MuiSelectProps } from '@mui/material/Select'
      5 | import InputLabel from '@mui/material/InputLabel'

      at Runtime.createScriptFromCode (node_modules/jest-runtime/build/index.js:1728:14)
      at Object.<anonymous> (src/components/Select/Select.tsx:2:1)

Test Suites: 1 failed, 1 total
Tests:       0 total
Snapshots:   0 total
Time:        3.272 s

import React from 'react'
import styled from '@mui/material/styles/styled'

import MuiSelect, { SelectProps as MuiSelectProps } from '@mui/material/Select'
import InputLabel from '@mui/material/InputLabel'
import MenuItem from '@mui/material/MenuItem'
import MuiFormControl from '@mui/material/FormControl'

interface ISelect extends MuiSelectProps {
  id: string
  label?: string
  options?: { text: string; option: string }[]
}
const FormControl = styled(MuiFormControl)`
  color: #fff;
  border-radius: 30px;
  width: 180px;
`

export const Select: React.FC<ISelect> = ({ label, id, children, options, ...props }) => {
  return (
    // @ts-ignore
    <FormControl fullWidth hiddenLabel>
      {label && (
        <InputLabel id={`input_${id}`} shrink={false}>
          {label}
        </InputLabel>
      )}
      <MuiSelect id={id} {...props}>
        {options && options.map(({ text, option }: { text: string; option: string }) => <MenuItem value={option}>{text}</MenuItem>)}
        {children && children}
      </MuiSelect>
    </FormControl>
  )
}

export default Select

Answer 1

首先，您的 Select.tsx 文件中有两个导出。只需使用默认导出，因此将第 20 行更改为:

const Select: React.FC<ISelect> = ({ label, id, children, options, ...props }) => {

然后在您的 Select.test.tsx 文件中更改为:

import Select from './Select'

最后，要解决导入问题，请将 Select.tsx 中的代码更改为:

import { styled } from '@mui/material'

这是一个相当普遍的问题，可以看出 here .