Jest 测试在 d3 导入时失败

我正在运行测试

import { render } from '@testing-library/react';
import MyComponent from '../../../../components/MyComponent';

test('renders MyComponent', () => {
  render(<MyComponent />);
});

在使用 d3 的 React 应用程序组件上，导入如下：

import React from 'react';
import * as d3 from 'd3';

使用命令

react-scripts test

这会在 d3 导入时产生错误：

Jest encountered an unexpected token

This usually means that you are trying to import a file which Jest cannot parse, e.g. it's not plain JavaScript.

By default, if Jest sees a Babel config, it will use that to transform your files, ignoring "node_modules".

Here's what you can do:
 • If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/en/ecmascript-modules for how to enable it.
 • 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/en/configuration.html

Details:

/Users/wogsland/Projects/sepia/node_modules/d3/src/index.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){export * from "d3-array";
                                                                                         ^^^^^^

SyntaxError: Unexpected token 'export'

我缺少什么？该组件在浏览器中工作正常，只是在最基本的测试中失败了。

要转换某些“node_modules”文件，您可以在配置中指定自定义“transformIgnorePatterns”。

从上面的建议中，我们可以告诉Jest不要解析ES模块node_modules.

In your jest.config.js文件中，您可以添加以下行。您可以将任何您想要的 ES 模块添加到阵列中。

const esModules = ['d3', 'd3-array', 'other-d3-module-if-needed'].join('|');

module.exports = {
  // ...
  transformIgnorePatterns: [`/node_modules/(?!${esModules})`],
  // ...
};