Jest -在使用transform属性时遇到意外令牌。

Question

我无法在我的测试中导入Svg，所以我遵循答案here。

我已经把这个添加到jest.config.js了

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

在我添加它之后，错误显示：

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() });

Answer 1

在我安装babel-jest并在transform中使用它之后，它就能工作了。

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

参考资料：

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