ts-jestが外部ライブラリをimportできない場合の対処方

  ● Test suite failed to run

    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:

    /プロジェクトディレクトリ/node_modules/なにかのパッケージ/index.js:7

    export * from './Hoge';
    ^^^^^^

    SyntaxError: Unexpected token 'export'

npm i -D babel-jest @babel/preset-env @babel/plugin-transform-modules-commonjs

module.exports = {
  presets: [
    [
      '@babel/preset-env',
      {
        targets: {
          node: 'current',
        },
      }
    ]
  ],
  plugins: [
    '@babel/plugin-transform-modules-commonjs',
  ]
}

"transform": {
  "\\.jsx?$": "babel-jest",
  "\\.tsx?$": "ts-jest"
}

"transformIgnorePatterns": [
  "/node_modules/(?!なにかのパッケージ|ESMが別パッケージのESMを呼んだりしているときは依存先も書く).+\\.js",
]