jest.config.js

module.exports = {
  roots: ['<rootDir>'],
  collectCoverageFrom: [
    '**/*.{js,jsx,ts,tsx}',
    '!**/*.d.ts',
    '!**/node_modules/**',
    '!**/cypress/**',
  ],
  setupFilesAfterEnv: ['<rootDir>/setupTests.ts'],
  moduleFileExtensions: ['js', 'ts', 'tsx', 'json', 'css', 'scss'],
  preset: 'ts-jest/presets/js-with-ts',
  // https://github.com/zeit/next.js/issues/8663#issue-490553899
  globals: {
    // we must specify a custom tsconfig for tests because we need the typescript transform
    // to transform jsx into js rather than leaving it jsx such as the next build requires. you
    // can see this setting in tsconfig.jest.json -> "jsx": "react"
    'ts-jest': {
      tsConfig: '<rootDir>/tsconfig.jest.json',
    },
  },
  testPathIgnorePatterns: ['/node_modules/', '/.next/', '/cypress/'],
  transformIgnorePatterns: [
    '/node_modules/',
    '[/\\\\]node_modules[/\\\\].+\\.(ts|tsx)$',
    '^.+\\.module\\.(css|sass|scss)$',
  ],
  transform: {
    '^.+\\.(js|jsx|ts|tsx)$': '<rootDir>/node_modules/babel-jest',
  },
  moduleNameMapper: {
    '.(css|less|sass|scss)$': 'identity-obj-proxy',
    '\\.(gif|ttf|eot|svg|png)$': '<rootDir>/test/__mocks__/fileMock.ts',
  },
  testEnvironment: 'jsdom',
};