为什么JEST不适用于import语句/ NEXTJS？

Question

我对JavaScript中的单元测试很陌生，我正在尝试为下一个JS项目编写一个单元测试，但我得到了这个错误的响应：

代码：

    import {isBase64} from '../../service/base64-service'

test('should return false for a invalid base64 string', () => {
        expect(
            isBase64('YWJj')
        )
            .toBe(false);
    }
)

错误：

● 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

Answer 1

我发现了我需要做的事，答案是在文件上：

#1:添加这种依赖性：

yarn add --dev  @babel/plugin-transform-modules-commonjs

#2:编辑.babelrc文件:如果没有它，在根文件夹中创建它

{
  "presets": ["next/babel"],
  "env": {
    "test": {
      "plugins": ["@babel/plugin-transform-modules-commonjs"]
    }
  },
  "plugins": []
}

现在，您的单元测试也将用于import语句。