开玩笑 - 使用转换属性时遇到意外的标记答案

【问题标题】：Jest - encountered an unexpected token when using transform property开玩笑 - 使用转换属性时遇到意外的标记
【发布时间】：2022-02-05 21:22:33
【问题描述】：

我无法在我的测试中导入 Svg，所以我按照答案 here。

我已将此添加到jest.config.js

"transform": {
   ...
   "^.+\\.svg$": "jest-svg-transformer"
}

我添加后，报错：

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:

    /Users/CCCC/Desktop/SourceTree/my-proj/src/setupTests.js:1
    ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import { configure } from "enzyme";
                                                                                      ^^^^^^

    SyntaxError: Cannot use import statement outside a module

      at Runtime.createScriptFromCode (node_modules/@jest/core/node_modules/jest-runtime/build/index.js:1728:14)

有人知道为什么会失败吗？

jest.config.js

module.exports = {
  moduleDirectories: ["node_modules", "src"],
  moduleNameMapper: {
    "^@/(.*)$": "<rootDir>/src/$1",
    "\\.(css|scss)$": "identity-obj-proxy",
  },
  transform: {
    "^.+\\.svg$": "<rootDir>/src/svgTransform.js",
  },
  setupFilesAfterEnv: ["<rootDir>/src/setupTests.js"],
  snapshotSerializers: ["enzyme-to-json/serializer"],
};

setupTest.js

import { configure } from "enzyme";
import Adapter from "enzyme-adapter-react-16";

configure({ adapter: new Adapter() });

【问题讨论】：

标签： javascript reactjs unit-testing testing jestjs

【解决方案1】：

在我安装babel-jest 并在transform 中使用它之后，它就可以工作了。

    "transform": {
      "^.+\\.js$": "babel-jest", // added this line
      ...
    }

参考：
How to resolve "Cannot use import statement outside a module" in jest

【讨论】：