rickvanlieshout.com/tests/jest-preprocess.js

'use strict';

const babelOptions = {
  presets: ['@babel/react', '@babel/env'],
  plugins: [
    '@babel/plugin-proposal-optional-chaining',
    '@babel/plugin-proposal-class-properties'
  ],
};

module.exports = require('babel-jest').createTransformer(babelOptions);