How to fix an error while installing React Jest?

Question

Software testing

I just started to understand Jest and this is not a task, at the very beginning there was an error, I can’t find a solution, I installed everything according to the docks and tutorials:

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:
       • 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://facebook.github.io/jest/docs/en/configuration.html
      Details:
         9 | describe('<App />', () => {
        10 |     it('should render App', () => {
      > 11 |         const wrapper = shallow(<App />);
           |                                 ^
        12 |     })
        13 | })

Most likely, he missed something and did not set it up, but still followed the description found on the Internet. Tell me what's wrong?

Answer 1

Resolved:
I didn't read the docs carefully and used more third-party resources :)
1. added the .babelrc file
2. installed npm install --save-dev babel-preset-stage-2
3. installed babel-plugin-transform-export-extensions
4. added the config to the created file in step 1

{
    "env": {
    "test": {
      "presets": ["env", "react", "stage-2"],
      "plugins": ["transform-export-extensions"],
      "only": [
        "./**/*.js",
        "node_modules/jest-runtime"
      ]
    }
  }
}