jest.config.js

module.exports = {
  preset: 'ts-jest',

  // The root of your source code, typically /src
  // `<rootDir>` is a token Jest substitutes
  roots: ['<rootDir>/src'],

  // Jest transformations -- this adds support for TypeScript
  // using ts-jest
  transform: {
    '^.+\\.(ts|tsx)?$': 'ts-jest',
    '^.+\\.(js|jsx)$': 'babel-jest',
  },

  // Runs special logic, such as cleaning up components
  // when using React Testing Library and adds special
  // extended assertions to Jest
  setupFilesAfterEnv: ['@testing-library/jest-dom/extend-expect'],

  // Test spec file resolution pattern
  // Matches parent folder `__tests__` and filename
  // should contain `test` or `spec`.
  testRegex: '(/__tests__/.*|(\\.|/)(test|spec))\\.tsx?$',
  // transformIgnorePatterns: [`/node_modules/*`],
  // Module file extensions for importing
  moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node'],
  testEnvironment: 'jsdom',
  verbose: true,
};